OPINION OF ADVOCATE GENERAL

ĆAPETA

delivered on 13 January 2022 ( 1 )

Joined Cases C‑415/20, C‑419/20 and C‑427/20

Gräfendorfer Geflügel- und Tiefkühlfeinkost Produktions GmbH (C‑415/20)

F. Reyher Nchfg. GmbH & Co. KG vertr. d. d. Komplementärin Verwaltungsgesellschaft F. Reyher Nchfg. mbH (C‑419/20)

v

Hauptzollamt Hamburg (C‑415/20 and C‑419/20)

and

Flexi Montagetechnik GmbH & Co. KG

v

Hauptzollamt Kiel (C‑427/20)

(Requests for a preliminary ruling from the Finanzgericht Hamburg (Finance Court, Hamburg, Germany))

(Reference for a preliminary ruling – Reimbursement of sums levied by a Member State in breach of EU law – Payment of interest – Customs union – Article 241 of Regulation (EEC) No 2913/92 (Community Customs Code) – Article 116(6) of Regulation (EU) No 952/2013 (Union Customs Code) – Limitation on the payment of interest in the event of reimbursement of customs duties – Principle of effectiveness – National measures providing for the payment of interest from the time when proceedings are brought before the courts)

I. Introduction

1. These three requests for a preliminary ruling submitted by the Finanzgericht Hamburg (Finance Court, Hamburg, Germany) concern the interpretation of EU law regarding the right of persons to payment of interest established in the Court’s case-law as a remedy arising under EU law. They relate to three different situations involving claims for the payment of interest on sums unduly levied in breach of EU law in connection with, first, the late payment of export refunds on agricultural products and the repayment of financial penalties wrongly imposed in relation to such refunds, second, the reimbursement of anti-dumping duties and, third, the reimbursement of import duties.

2. The questions raised by the present cases provide the Court with the opportunity to explain and develop its case-law on the right to payment of interest, and in particular to address the question of in which situations of infringement of EU law such a right arises as a matter of EU law. Additionally, the Court is called upon to clarify the conditions under which limitations may be put on the right to payment of interest by both EU law and national law.

II. Legal framework

A. EU law

3. Council Regulation (EEC) No 2913/92 of 12 October 1992 establishing the Community Customs Code ( 2 ) was repealed and replaced by Regulation (EC) No 450/2008 of the European Parliament and of the Council of 23 April 2008 laying down the Community Customs Code (Modernised Customs Code), ( 3 ) which was itself repealed and replaced by Regulation (EU) No 952/2013 of the European Parliament and of the Council of 9 October 2013 laying down the Union Customs Code. ( 4 )

4. Article 241 of the Community Customs Code provided: ‘Repayment by the competent authorities of amounts of import duties or export duties or of credit interest or interest on arrears collected on payments of such duties shall not give rise to the payment of interest by those authorities. However, interest shall be paid: – where a decision to grant a request for repayment is not implemented within three months of the date of adoption of that decision, – where national provisions so stipulate. …’

5. Article 116(6) of the Union Customs Code states: ‘Repayment shall not give rise to the payment of interest by the customs authorities concerned. However, interest shall be paid where a decision granting repayment is not implemented within three months of the date on which that decision was taken, unless the failure to meet the deadline was outside the control of the customs authorities. In such cases, the interest shall be paid from the date of expiry of the three-month period until the date of repayment. The rate of interest shall be established in accordance with Article 112.’

B. German law

6. According to the referring court, the relevant German law is the Abgabenordnung (Tax Code) (BGBl. 2002 I, p. 3866), in the version applicable to the disputes in the main proceedings (‘the AO’).

7. Paragraph 3 of the AO states: ‘… (3) Import and export duties pursuant to Article 5(20) and (21) of the [Union Customs Code] shall be taxes within the meaning of this Code. … (4) “Ancillary tax payments” are … interest pursuant to Paragraphs 233 to 237, … interest on import and export duties pursuant to Article 5(20) and (21) of the Union Customs Code … …’

8. According to Paragraph 233 of the AO: ‘Interest shall be charged on claims arising from the tax debtor-creditor relationship (Paragraph 37) only to the extent that this is legally prescribed. …’

9. Paragraph 236 of the AO provides: ‘(1) Subject to the provisions of subparagraph 3 below, where an assessed tax is reduced or a tax rebate granted by final and binding judicial ruling or as a result of such a ruling, interest shall accrue on the amount to be refunded or rebated from the date proceedings commence to the date of payment. … …’

10. Additionally, in Case C‑415/20, the relevant legislation includes the Gesetz zur Durchführung der gemeinsamen Marktorganisationen und der Direktzahlungen (Law implementing the common organisation of markets and direct payments) (BGB1. 2017 I, p. 3746), in the version applicable to the dispute in the main proceedings (‘the MOG’).

11. Paragraph 14 of the MOG states: ‘1. Amounts due for the repayment of a benefit or the breach of any other obligation shall bear interest at the basic rate plus five percentage points from the day on which they become due. Any duty not paid in time shall bear interest at the basic rate plus five percentage points from the date on which it falls due. The first and second sentences shall apply subject to the provisions and acts referred to in Paragraph 1(2). 2. Amounts due in respect of a benefit or intervention shall bear interest from the date of referral to the court, in accordance with Paragraphs 236, 238 and 239 of the AO. They shall not otherwise give rise to the payment of interest.’

III. Facts, main proceedings and questions referred

A. Case C‑415/20

12. According to the order for reference, Gräfendorfer Geflügel- und Tiefkühlfeinkost Produktions GmbH (‘Gräfendorfer’) is a German company which exports poultry carcasses to third countries.

13. In the period between January and June 2012, the Hauptzollamt Hamburg (Principal Customs Office, Hamburg, Germany) refused to grant Gräfendorfer export refunds on the ground that the poultry carcasses were not of fair marketable quality, since they had not been fully plucked or had too many giblets (offal). On the basis of relevant EU law, ( 5 ) the Principal Customs Office, Hamburg also imposed penalties on Gräfendorfer because it had applied for a larger export refund than that to which it was entitled.

14. Thereafter, in actions brought by persons other than Gräfendorfer, ( 6 ) the Finanzgericht Hamburg (Finance Court, Hamburg) ruled, on the basis of the Court’s judgment of 24 November 2011, Gebr. Stolle, ( 7 ) that the presence of a small number of feathers was not prejudicial to an export refund and that a total of up to four giblets was permissible. Consequently, the Principal Customs Office, Hamburg allowed the administrative complaint brought by Gräfendorfer, granting it the export refunds claimed and reimbursing it for the penalties imposed.

15. By letter of 16 April 2015, Gräfendorfer submitted an application to the Principal Customs Office, Hamburg for payment of interest on the late payment of export refunds and on the refunded penalties. By decision of 22 July 2015, the Principal Customs Office, Hamburg rejected that application. It also rejected, by decision of 18 April 2018, Gräfendorfer’s administrative complaint against its decision of 22 July 2015.

16. On 23 May 2018, Gräfendorfer brought an action challenging that rejection before the referring court. In support of its action, it relies on EU law and the right to payment of interest arising from the Court’s case-law. The Principal Customs Office, Hamburg submits, inter alia, that its refusal, at the time, to grant the export refunds was not contrary to EU law, but in accordance with the applicable EU legislation and national case-law; it was only the result of the Court’s judgment and the referring court’s subsequent decisions that Gräfendorfer was entitled to the grant of export refunds and, in such a situation, it cannot claim interest on the corrected amount. The Principal Customs Office, Hamburg invoked in that respect the Court’s judgment of 18 January 2017, Wortmann. ( 8 )

17. The referring court indicates that there is no provision of EU legislation or national law applicable to the dispute in the main proceedings which makes it possible to uphold Gräfendorfer’s claims for interest on either the late payment of export refunds or the refunded penalties. Therefore, the outcome of the dispute depends on whether those claims can be based on the right to payment of interest under EU law, as set out in the Court’s case-law.

18. Since it was uncertain whether the right to payment of interest based on EU law arises in a situation of infringement of EU law such as the one in that case, the Finanzgericht Hamburg (Finance Court, Hamburg) decided to stay the main proceedings and to refer the following questions to the Court for a preliminary ruling: ‘(1) Does the requirement under EU law for Member States to repay, with interest, duties levied in breach of EU law also apply where the reason for the repayment is not a finding by the Court of Justice of the European Union that a provision of EU law has been breached, but that the Court of Justice has interpreted a (sub)heading of the Combined Nomenclature? (2) Do the principles relating to a claim to interest established by the Court of Justice of the European Union also apply to the payment of export refunds refused by the Member State authority in breach of EU law?’

B. Case C‑419/20

19. According to the order for reference, F. Reyher Nchfg. GmbH & Co. KG (‘Reyher’) is a German company which imported into the EU, during the years 2010 and 2011, fasteners from a company in Indonesia and which is a subsidiary of a company established in China.

20. The Principal Customs Office, Hamburg took the view that those fasteners originated in China and should be subject, when imported into the EU, to the anti-dumping duties set out in Regulation No 91/2009. ( 9 ) Consequently, in 2013, the Principal Customs Office, Hamburg issued several notices levying anti-dumping duties on Reyher, which it paid. Thereafter, Reyher brought an action challenging the imposition of those duties before the Finanzgericht Hamburg (Finance Court, Hamburg).

21. By judgment of 3 April 2019, which has become final, the Finanzgericht Hamburg (Finance Court, Hamburg) upheld Reyher’s action and set aside the anti-dumping duties imposed on it on the ground that the Principal Customs Office, Hamburg failed to prove that the fasteners imported into the EU by Reyher originated in China.

22. In May 2019, the Principal Customs Office, Hamburg reimbursed Reyher for the anti-dumping duties it had paid. However, it refused Reyher’s claim for the payment of interest on those duties, and then rejected Reyher’s administrative complaint against that refusal.

23. On 10 February 2020, Reyher brought an action challenging that refusal before the referring court. Even though the parties are in dispute as to whether the payment of interest is excluded on the basis of Article 116(6) of the Union Customs Code, the referring court considers that it is not that code, but the earlier Community Customs Code that is applicable to the facts of the case. Under Article 241 of the Community Customs Code, interest is payable where stipulated by national law. Therefore, the referring court considers that Reyher could claim interest dating from the beginning of judicial proceedings on the basis of Paragraph 236(1) of the AO. However, that court wonders whether Reyher is entitled to interest for the period from the payment of the undue anti-dumping duties to the commencement of judicial proceedings.

24. Being uncertain whether Reyher can rely on the right to payment of interest which arises under EU law in accordance with the Court’s case-law in respect of the interest which it cannot claim on the basis of national law, the Finanzgericht Hamburg (Finance Court, Hamburg) decided to stay the main proceedings and to refer the following question to the Court for a preliminary ruling: ‘Is there an infringement of EU law, which is a condition for entitlement to interest under EU law as developed by the Court of Justice of the European Union, where a Member State authority imposes a duty pursuant to EU law but a Member State court subsequently finds that the factual conditions for the imposition of the duty have not been met?’

C. Case C‑427/20

25. According to the order for reference, Flexi Montagetechnik GmbH & Co. KG (‘Flexi Montagetechnik’) is a German company which imported into the EU bolt hooks which are used in the production of dog leashes.

26. The Hauptzollamt Kiel (Principal Customs Office, Kiel, Germany) took the view, following an external customs examination, that those bolt hooks should not be classified under heading 8308 of the combined nomenclature (‘CN’), entailing a 2.7% rate of customs duty, as declared by Flexi Montagetechnik, but as goods classified under CN heading 7907, entailing a 5% rate of custom duty, and thus subject to import duties of a higher amount than that paid by Flexi Montagetechnik. The Principal Customs Office, Kiel issued two notices for the recovery of import duties, which Flexi Montagetechnik paid in March 2014. Thereafter, in September 2014, Flexi Montagetechnik brought an action before the courts against those notices.

27. By judgment of 20 June 2017, the Bundesfinanzhof (Federal Finance Court, Germany) set aside those notices on the ground that the recovery of the import duties was unlawful because the bolt hooks should have been classified under CN heading 8308, as Flexi Montagetechnik had done.

28. In October 2017, the Principal Customs Office, Kiel reimbursed Flexi Montagetechnik for the import duties it had paid. However, it refused to pay interest on those duties for the period from the date of payment to the date of reimbursement, and then rejected Flexi Montagetechnik’s administrative complaint against that refusal.

29. Flexi Montagetechnik brought an action challenging that refusal before the referring court. In the course of the proceedings, the Principal Customs Office, Kiel granted it interest for the period from the bringing of the action against the recovery notices (September 2014) until the reimbursement of the import duties (October 2017). However, the parties are still in dispute as to whether Flexi Montagetechnik can also claim interest for the period from the payment of the import duties unlawfully levied (March 2014) until the bringing of the action against the recovery notices (September 2014).

30. Being uncertain whether Flexi Montagetechnik can rely on the right to payment of interest which arises under EU law in accordance with the Court’s case-law in respect of the interest which it cannot claim on the basis of national law, the Finanzgericht Hamburg (Finance Court, Hamburg) decided to stay the main proceedings and to refer the following question to the Court for a preliminary ruling: ‘Is there an infringement of EU law, which is a condition for entitlement to interest under EU law as developed by the Court of Justice of the European Union, where a Member State authority imposes a duty in breach of legally valid provisions of EU law and a Member State court makes a finding of that infringement of EU law?’

IV. Procedure before the Court

31. By decision of 9 October 2020, the President of the Court of Justice decided to join Cases C‑415/20, C‑419/20 and C‑427/20 for the purposes of the written procedure, the oral procedure and the judgment.

32. Written observations were submitted to the Court by Gräfendorfer, Reyher, Flexi Montagetechnik, the Netherlands Government and the European Commission. Those parties also replied to written questions put to them by the Court pursuant to Article 62(1) of its Rules of Procedure.

V. Analysis

33. By its questions, the referring court seeks guidance on several issues concerning the right to payment of interest based on EU law as developed in the Court’s case-law.

34. The referring court does not question that the right to payment of interest arises under EU law, but is uncertain whether such a right arises in the different situations of infringement of EU law with which it is faced.

35. The first question underlying all three cases is, in essence, whether it matters how the infringement of EU law happened for the right to payment of interest to arise as a matter of EU law. Additionally, the question indirectly arises as to whether it matters that the infringement of EU law was established by the national courts and not by the Court of Justice.

36. The second question underlying these cases is essentially whether and under what conditions the right to payment of interest which arises as a matter of EU law can be limited. Cases C‑419/20 and C‑427/20 raise the question of the applicability of the limitation on the right to payment of interest envisaged under EU customs legislation, while all three cases raise the question of the possibility to limit that right by national law.

37. With a view to answering those questions, I will first consider the right to payment of interest as developed in the Court’s case-law relating to the reimbursement of sums paid contrary to EU law (section A). I will next examine whether, for the right to payment of interest to arise under EU law, it matters how the infringement of EU law happened (section B.1), after which I will discuss whether it matters that the infringement of EU law is established by the national courts or the Court of Justice (section B.2). Finally, I will address the possible justifications of the limitations put on the right to payment of interest, both under EU law (section C.1) and under national law (section C.2).

38. My analysis will show that the right to payment of interest is a general rule of EU law applicable in all situations when payment due under EU law is made with a delay, whether the situation concerns reimbursement of unduly paid sums of money or delayed payment of benefits to which a person is entitled under EU law. Such a general rule can be limited by EU law or by national law, provided that that limitation is justified by an acceptable public interest and is proportionate to that interest. I will examine the limitation introduced by EU customs legislation, as well as the limitation that exists under the applicable national law in that light.

A. The right to payment of interest under EU law

39. It should be observed at the outset that the right to payment of interest as a matter of EU law has developed together with the Court’s case-law on the right to reimbursement of sums unduly paid in breach of EU law.

40. The situations in which different charges were imposed contrary to EU law are not novel. In early case-law, the Court was faced, for example, with charges for phytosanitary inspections, ( 10 ) export charges, ( 11 ) health inspection charges on imports, ( 12 ) levies on pig carcasses intended for the manufacture of bacon, ( 13 ) consumption taxes on bananas ( 14 ) and charges levied on the registration of public and private limited companies. ( 15 ) The more recent cases concerned the advance payment of corporation tax on profits distributed by a subsidiary to its parent company, ( 16 ) overcharged value added tax (VAT), ( 17 ) a pollution tax on motor vehicles ( 18 ) and overpaid taxes on electricity consumption, ( 19 ) to name just a few.

41. When such charges were found to be contrary to EU law, the persons who paid them requested their reimbursement. Those claims were often coupled with claims for the payment of interest.

42. However, EU law does not contain any written general rules about rights or remedies available to persons who paid sums contrary to EU law. That area of law was therefore developed, and is still being developed, through the Court’s case-law. The following is a short overview of my understanding of that case-law.

43. According to settled case-law, the right to reimbursement of sums levied by a Member State in breach of EU law is the consequence and complement of the rights conferred on individuals by provisions of EU law, as interpreted by the Court. The Member States are therefore required in principle to repay sums levied in breach of EU law. ( 20 )

44. In my view, it clearly follows from that case-law that the right to reimbursement is itself a right that arises under EU law in the situation in which a person paid sums contrary to EU law. ( 21 )

45. Furthermore, the Court has considered that, where a Member State has levied charges in breach of the rules of EU law, individuals are entitled to reimbursement not only of the tax unduly levied, but also of the amounts paid to that State or retained by it which relate directly to that tax. That also includes losses constituted by the unavailability of sums of money paid. ( 22 )

46. The Court has additionally explained that it is clear from that case-law that the principle that the Member States are obliged to repay with interest amounts of tax levied in breach of EU law follows from EU law. ( 23 )

47. I read the cited case-law to mean that whenever the right to reimbursement arises under EU law, it is coupled with the right to payment of interest. Such an interpretation of the case-law is endorsed by the Court’s Advocates General ( 24 ) and by scholars. ( 25 )

48. The question which, however, was still not clearly addressed in the case-law is whether interest is owed in all situations when the right to reimbursement is based on EU law, or whether there exist situations in which EU law grants the right to reimbursement, but does not require the payment of interest. Furthermore, it is not yet clarified whether the right to payment of interest arises only together with the right to reimbursement under EU law, or whether it also arises in other situations in which the payment obligation performed with delay is based directly on EU law (such as the export refunds in Case C‑415/20).

49. The answer to that question must lie, in my view, also in EU law, and it does not depend on the national legal systems. In other words, the scope of the right to payment of interest is not a matter of national procedural autonomy. That term refers to the competences of the Member States to regulate in their legal systems issues of substance and procedure relevant for the exercise of EU remedial rights (such as the right to reimbursement or the right to damages as they arise under EU law), where the EU rules necessary for their implementation are lacking. However, the question whether the right to payment of interest arises in all or only in some situations in which the right to reimbursement has arisen, or also in other situations when the pecuniary obligation is based on EU law is a question of the existence of that right, and not of its implementation, and is therefore entirely a matter of EU law. On the contrary, the question whether such a right, when it exists under EU law, may be limited by the national legal systems is a different kind of question, which I will deal with separately below (see section C.2).

B. The infringement of EU law giving rise to the right to reimbursement with interest under the Court’s case-law

1. Does it matter how the infringement of EU law happened?

50. One of the issues raised by the present cases relates to whether it matters, for the purposes of the Court’s case-law on the recovery of undue payments with interest, how the infringement of EU law happened. More precisely, the question arises as to whether interest is payable only in cases in which the EU or national measure serving as the legal basis for the imposition of the sums unduly levied is annulled or invalidated, as the Netherlands Government argues, or whether interest is payable, as indicated by the referring court, Gräfendorfer, Reyher, Flexi Montagetechnik and the Commission, in respect of any type of infringement of EU law.

51. In that regard, the referring court explains that the common feature of the cases in which the Court considered that the applicants were entitled to interest as a matter of EU law was that the right to reimbursement arose after the invalidation of the legal basis for payment by the Court. ( 26 )

52. By contrast, the infringement of EU law in the present cases stemmed from the fact that the competent national authorities had erred in the interpretation of EU law or in the assessment of facts when applying legally valid rules of EU law. In Case C‑415/20, the infringement consisted in an erroneous interpretation of valid EU legislation, under which the applicant was denied payment of export refunds and was additionally fined by the competent national authorities. In Case C‑419/20, the infringement consisted in an error in the assessment of facts by the competent national authorities which led to the imposition of anti-dumping duties which were not due under the valid EU law and, in Case C‑427/20, the imposition of import duties was the result of an incorrect interpretation of valid EU law by such authorities.

53. It is true that the cases invoked by the referring court concerned situations in which the legal basis for payment was invalidated. The Zuckerfabrik Jülich judgment ( 27 ) involved the payment of interest on sums unduly paid in respect of production levies in the sugar sector on the basis of EU regulations which the Court had declared invalid. The Irimie judgment ( 28 ) related to the payment of interest on a reimbursed pollution tax imposed by national law found to be contrary to EU law on the basis of the Court’s interpretation. Finally, the Wortmann judgment ( 29 ) concerned the payment of interest in connection with the reimbursement of anti-dumping duties which had been paid by the applicant pursuant to an EU regulation which had been partially annulled by the Court.

54. However, it should be pointed out that, first, there are cases decided by the Court in which the reason for the payment of interest was not the invalidation of the legal basis for payment, but some different infringement of EU law. One such case was mentioned by the referring court itself. ( 30 ) Second, there are, in my view, important conceptual reasons which militate in favour of an answer to the effect that there is a right to payment of interest under EU law no matter how the infringement of EU law arises. In other words, in my opinion, there is no justification for restricting the right to payment of interest exclusively to situations involving the invalidation of the legal basis for payment. To explain that position, I first need to look into the reasons that motivated the Court’s case-law which provides for the right to payment of interest.

(a) The purpose of the right to payment of interest

55. When a person has paid a sum of money contrary to EU law, the right to retrieve it arises at the same time, even if it might be confirmed by the Court of Justice or the national court at a later time. That follows from the case-law mentioned in point 43 of this Opinion, in which the Court explains that the right to a refund of charges levied in a Member State in breach of rules of EU law is the consequence and complement of the rights conferred on individuals by provisions of EU law not to pay those sums. Between the date when the right to reimbursement arose and the date when reimbursement takes place there is a period of time, sometimes even a significant one. ( 31 ) Interest serves to address that passage of time.

56. The obligation to pay interest does not represent a punishment or sanction on the competent national authorities in respect of the committed infringement of EU law, but rather aims to ensure that individuals have adequate compensation for losses sustained through the unavailability of the sums unduly levied in breach of EU law. In other words, the right to payment of interest is based on the idea of granting individuals restitutio in integrum for the impossibility to use those sums during a certain period. ( 32 )

57. Being simply a means to address the loss of value of money over time, the right to payment of interest does not depend on whether the competent national authorities believed that they acted in accordance with EU law, which was only subsequently interpreted differently from what those authorities considered to be its correct application at the time. The concern raised by the referring court in that respect, implying that those authorities might not be liable to pay interest because they have collected the charges in good faith is therefore irrelevant for the right to payment of interest to arise.

58. The right to payment of interest is not the same as the right to damages. In cases relating to reimbursement, it arises as a consequence of payment of sums of money contrary to EU law and is not dependent on the establishment of liability of the competent national authorities that committed the infringement of EU law. It is therefore irrelevant why the competent national authorities collected sums of money contrary to EU law. Similar to how the right to reimbursement as an EU remedy only reacts to the objective fact that those sums were not owed, the right to payment of interest reacts to the fact of the passage of time.

59. In cases in which the remedy in reimbursement arises, the interest covers the period of time during which a person was supposed to have the sums of money but did not have them, without the need for looking into the reasons why the competent national authorities committed a breach of EU law. The breach itself suffices. Interest simply addresses the passage of time and is therefore detached from the question of potential exculpation for the breach of EU law.

60. The case-law supports such an economic justification for the right to payment of interest. The Court has first pointed out the economic rationale of the right to reimbursement. It considered that ‘the right to the recovery of sums unduly paid helps to offset the consequences of the duty’s incompatibility with EU law by neutralising the economic burden which that duty has unduly imposed on the operator who, in the final analysis, has actually borne it’. ( 33 ) In a number of recent cases, as mentioned in point 45 of this Opinion, the Court has further explained that EU law requires the repayment of sums of money unduly levied together with interest, as the interest covers the ‘losses constituted by the unavailability of sums of money’ paid. ( 34 )

61. Therefore, the payment of interest is necessary to restore the respect for EU law by creating the situation which is the closest possible to the one which would have existed had the infringement of EU law not taken place. It, thus, aims to restore the effectiveness of EU law.

62. An alternative, or possibly additional, explanation for awarding interest, as invoked by the referring court, Gräfendorfer and Flexi Montagetechnik, is the concept of unjust enrichment. ( 35 )

63. That concept was relied on by Advocate General Sharpston in her Opinion in Zuckerfabrik Jülich and Others, ( 36 ) a case that also concerned reimbursement of sums claimed from national authorities, but which were collected for the benefit of the EU budget based on an invalid EU legal basis.

64. In addition, the Court has relied on unjust enrichment in its judgments of 16 December 2008, Masdar (UK) v Commission, ( 37 ) and of 9 July 2020, Czech Republic v Commission, ( 38 ) as a justification for the possibility to introduce an action claiming reimbursement from the EU on the basis of Article 268 TFEU and the second paragraph of Article 340 TFEU. The Court underlined that a person who has suffered a loss which increases the wealth of another person (in that case, the EU) without there being any legal basis for that enrichment has the right, as a general rule, to restitution from the person enriched, up to the amount of the loss. In the Court’s view, an action requiring reimbursement from the EU budget would require proof of enrichment on the part of the defendant for which there is no valid legal basis and proof of impoverishment on the part of the applicant which is linked to that enrichment.

65. If the concept of unjust enrichment might be a proper justification for an action brought by a Member State claiming reimbursement of sums which it has unduly paid into the EU budget, reliance on that concept is, in my opinion, not necessary to justify payment of interest in situations such as those in the present cases. It may even create an obstacle to the payment of interest. Due to the organisation of governance in the EU, different sums are often collected by national authorities for the benefit of the EU budget. In line with the case-law mentioned in the previous point of this Opinion, a person who paid sums which were unduly levied would have to prove enrichment of the national authorities which collected those sums. If those sums were transferred to the EU budget, proving the enrichment of the national authorities might not be possible.

66. Rather than relying on the unjust enrichment logic, the right to payment of interest focuses on the other side of such a relation – the unjust impoverishment. Its aim is to ensure the effectiveness of EU law by restoring the person impoverished contrary to EU law to the situation which would have existed had the infringement not happened. What matters, therefore, is the impoverishment of the applicant, rather than the enrichment of the national authorities. The proof of enrichment is not necessary for the right to payment of interest on the basis of EU law. ( 39 )

67. In my opinion, the economic justification which the Court has offered for the existence of the right to payment of interest supports the conclusion that, in EU law, that right arises whenever a person is impoverished contrary to EU law, without the need to ask whether the subject which committed the infringement acted bona fide or not, and whether it was enriched.

(b) Is there a right to payment of interest in the present cases?

68. If it is accepted that EU law grants the right to payment of interest in order to restore its effectiveness by covering the loss of the value of money during the period in which a person was deprived of it contrary to EU law, there is no justification for distinguishing between different situations of infringement of EU law.

69. The interest is due whether the infringement consisted in an invalid EU or national legal basis for payment, wrong interpretation of EU law or national law implementing it, wrong assessment of facts leading to collection of sums of money contrary to EU law, or any other infringement.

70. In my view, it could be implied from the case-law that the right to payment of interest arises in all situations in which a sum of money is owed under EU law with a view to covering the passage of time from the moment when the entitlement to payment arose until the payment was made. ( 40 ) The right to payment of interest arises as a consequence of the infringement of the EU norm granting a right to payment or to non-payment from the time when that right was infringed and it serves to restore the effectiveness of EU law.

71. Therefore, in situations in which the right to reimbursement arose because of the invalidation of the legal basis for payment which infringed EU law, the payment of interest is necessary to reinstate the situation which would have occurred if the invalidated act had never been adopted. ( 41 )

72. Likewise, the payment of interest is necessary for similar reasons in situations in which reimbursement is claimed as a result of the wrong assessment of facts or erroneous interpretation of law. In Case C‑415/20, the applicant would not have been obliged to pay financial penalties had the competent national authorities correctly interpreted EU law. To restore the situation which would have existed had the infringement of EU law not happened, it is not sufficient merely to repay those penalties, but to pay interest as well in order to cover the passage of time. Only in that way can the effectiveness of EU law be restored.

73. That reasoning is also applicable in Cases C‑419/20 and C‑427/20. The effectiveness of EU law can only be restored if the applicants are ‘returned’ to a situation in which the infringement of EU law committed by wrong assessment of facts or erroneous interpretation of EU law has not occurred. That necessitates the coverage for the loss of the value of money of which the applicants were deprived because of the infringement of EU law.

74. That approach is confirmed in recent case-law, in which the Court held that interest is payable also in situations in which the applicants’ right to reimbursement did not result from the invalidation of the legal basis for payment, but from the incorrect interpretation of the law or the facts leading to the undue payment. In the Littlewoods Retail judgment, ( 42 ) the applicant overpaid VAT due to the incorrect interpretation of the relevant EU and national law. In the Hauptzollamt B judgment, ( 43 ) the reimbursement was the consequence of miscalculated taxes on electricity. In both cases, the Court considered that the applicants were entitled to payment of interest as a matter of EU law.

75. The situation in Case C‑415/20, in which the applicant was, for a certain time, deprived of the payment of the export refunds to which it was entitled under EU law, differs from cases relating to reimbursement. In those cases, the right to payment of interest arose as a result of the infringement of the right not to pay, whereas in Case C‑415/20, the right to payment of interest was claimed in connection with the right to receive a payment. The second question of the referring court in that case therefore, in essence, asks whether the right to payment of interest arises only together with the right to reimbursement, or whether it also arises in a situation when a person’s right to payment based directly on EU law is infringed.

76. If, as I suggested, the right to payment of interest under EU law is justified by the necessity to restore the effectiveness of EU law, covering the passage of time during which an individual was deprived of a sum of money contrary to EU law, the right to payment of interest also arises when the infringement consists in the refusal of payment to which a person was entitled under EU law. The interest is payable in the situation in Case C‑415/20 from the moment when the right to export refunds was created to the moment when such export refunds were paid.

77. In conclusion, in my view, the Court’s case-law should be understood as including, as a general rule, the right to payment of interest in all situations in which sums of money owed on the basis of EU law are paid with delay in breach of EU law.

78. Therefore, I consider that the Court’s case-law on the right to payment of interest applies to export refunds wrongly refused and to financial penalties wrongly imposed by the competent national authorities in breach of EU law, such as in Case C‑415/20. It also applies to the reimbursement of anti-dumping duties collected on the basis of wrongly established facts, such as in Case C‑419/20, and to the reimbursement of import duties wrongly collected as a result of an erroneous interpretation of EU law, such as in Case C‑427/20. In all those situations, the purpose of the payment of interest is the same – to cover the loss of value of money caused by the passage of time from the moment of the entitlement to the sums of money at issue until the moment of their payment.

79. Interpreting the Court’s case-law as limited to situations where an EU or national measure is annulled or invalidated by the Court would undermine the very objective of the case-law, which is to ensure that, however EU law is infringed, there is a right to payment of interest granted to individuals in order to restore the effectiveness of EU law.

2. Does it matter whether the national courts or the Court of Justice find the infringement of EU law?

80. As a related point, the interpretation of the concept of infringement of EU law in the Court’s case-law on the recovery of sums unduly levied for the purposes of the present cases also indirectly raises the question whether it matters that it is the national courts or the Court of Justice which find the infringement of EU law.

81. In my view, that question must be answered in the negative.

82. As the Court has recognised, Article 19 TEU entrusts the responsibility for ensuring the full application of EU law in all Member States and the judicial protection that individuals derive from EU law to the national courts and to the Court of Justice. ( 44 ) Consequently, national courts, in collaboration with the Court of Justice, fulfil a duty entrusted to them jointly of ensuring that, in the interpretation and application of the Treaties, the law is observed. ( 45 )

83. Furthermore, the Court has emphasised that the procedure governed by Article 267 TFEU establishes between the Court of Justice and national courts direct cooperation as part of which the latter are closely involved in the correct application and uniform interpretation of EU law and also in the protection of individual rights conferred by it. Accordingly, the tasks attributed to the national courts and to the Court of Justice, respectively, are indispensable to the preservation of the very nature of the law established by the Treaties. ( 46 )

84. It follows from this that the national courts play a seminal role, alongside the Court of Justice, as ‘ordinary’ courts within the EU legal order. ( 47 ) Therefore, if a national court establishes an infringement of EU law, this has the same value as that established by the Court of Justice in respect of the right to reimbursement of sums unduly levied and the corresponding interest granted to individuals under EU law.

85. It should also be pointed out that this approach appears to be reflected in the Court’s case-law in this context. In the Wortmann judgment, ( 48 ) the Court indicated that, where duties are reimbursed on the ground that they were levied in breach of EU law, ‘which is a matter for the referring court to determine’, there is an obligation on the Member States under EU law to pay the corresponding interest.

86. Therefore, I take the view that there is an infringement of EU law that gives rise to the right to payment of interest whether it is the national courts or the Court of Justice which find that infringement.

C. Limitations which may be imposed on the right to payment of interest by EU and national law

87. In all three cases, the referring court considers that the applicants are entitled to payment of interest for the entire period in which they were deprived of the sums of money contrary to EU law only if a right to payment of interest exists under EU law. In the preceding sections of this Opinion, I expressed the view that EU law indeed entitles the applicants to the payment of interest.

88. However, it is clear from the orders for reference that the referring court considers that, at least in Cases C‑419/20 and C‑427/20, the applicants were entitled to payment of interest under national law for the period from the initiation of the judicial proceedings until the date of reimbursement, while in Case C‑415/20, the applicant is not entitled to any interest under national law because it did not bring an action demanding the payment of export refunds before a court.

89. In that regard, it is, in my view, irrelevant whether national law grants the applicants the right to payment of interest in the present cases, since that right was created directly on the basis of EU law. Therefore, the question that arises as relevant for the decision of the referring court is not whether interest may be granted on the basis of EU law for the period until the initiation of the judicial proceedings, but rather, whether the rules of national law may lawfully limit the exercise of the right to payment of interest based on EU law in relation to that period, or condition it by the necessity to introduce an action in court.

90. Likewise, the question arises whether the applicants may be deprived of the payment of interest to which they are otherwise entitled under EU law on the basis of the application of EU customs legislation.

91. Rights which arise under EU law, including the right to payment of interest, may, under certain conditions be limited either by EU law itself or by national law.

92. Broadly speaking, for the limitation of EU rights to be accepted, two conditions have to be fulfilled: first, the measure limiting the EU right has to be justified by a public interest objective acceptable under EU law and, second, that measure has to be proportionate in relation to that objective.

93. It is under that framework that I now turn to examine two limiting measures relevant to the present cases, the first, one of EU law and, the second, one of national law.

1. Limitations imposed by EU law (Article 241 of the Community Customs Code and Article 116(6) of the Union Customs Code)

94. One of the questions which necessitates an answer in the present cases is whether Article 241 of the Community Customs Code and Article 116(6) of the Union Customs Code (to which I shall refer jointly as ‘the Customs Code’) apply to the circumstances of the cases pending before the referring court.

95. Those provisions of EU law respectively limit and exclude, subject to certain qualifications, the payment of interest in the event of the reimbursement of customs duties by the competent national authorities. They are therefore potentially relevant in respect of the reimbursement of the import duties at issue in Case C‑427/20, as well as the reimbursement of anti-dumping duties at issue in Case C‑419/20.

96. According to the arguments put forward by the Netherlands Government, the rule excluding interest embodied in the Customs Code applies to the circumstances of Cases C‑419/20 and C‑427/20, which is why interest is not payable in those cases. Gräfendorfer, Reyher, Flexi Montagetechnik and the Commission disagree. They claim, relying on the Wortmann judgment, that the Customs Code rule that excludes the payment of interest does not apply to the circumstances of those cases.

97. The Netherlands Government builds its argument starting from the position that the Customs Code rule excluding the payment of interest is a general rule. It refers to the findings of the Court in the Wortmann judgment as an exception to that rule.

98. Contrary to that position, I am of the opinion that the Customs Code rule at issue is not a general rule, but rather an exception to the general rule of EU law that interest is payable in situations involving the reimbursement of sums paid contrary to EU law. Precisely because the general rule demands the payment of interest, it was necessary to exclude it by an express rule.

99. As a limitation to the general rule, the Customs Code rule has to be justified and proportionate to the justification offered. Without such a justification, the Customs Code rule excluding interest in the event of reimbursement would be invalid. ( 49 )

100. The Wortmann judgment ( 50 ) offered the justification for the Customs Code rule at issue, ( 51 ) but limited, at the same time, its application to certain types of situations only. I will explain that this was necessary to safeguard the legality of the Customs Code rule, and that, for the same reason, that rule is not applicable to the present cases.

101. In the Wortmann judgment, the Court, following the line of reasoning put forward by the Advocate General in that case, held that the legislative history of Article 241 of the Community Customs Code indicates that it applies ‘to a situation in which, after the customs authority has released the merchandise concerned, it becomes apparent that the initial calculation of the import duties should be revised downwards and, therefore, that all or a part of the import duties paid by an operator must be repaid to him [or her]’. ( 52 )

102. As explained by Advocate General Campos Sánchez-Bordona, ‘the customs authority does not inspect goods before releasing them and only later carries out checks on whether imports were properly carried out. If, at that later date, a new assessment is required, it may lead either to the importer having to pay what he [or she] had hitherto not paid (initial under-assessment) or to the customs authority having to reimburse the amount overpaid’. ( 53 ) In either of the two situations, the Customs Code excludes the payment of interest. ( 54 )

103. Therefore, the justification for the Customs Code limitation of the general rule which requires payment of interest lies in enabling the speedy customs clearance system and the quick release of goods into circulation on the market. ( 55 )

104. In order for that rule to remain proportionate to the aim it is designed to achieve, its application has to be confined to the situations of customs clearance procedures as explained in the preceding points of this Opinion. Those are the situations in which either the customs authority or an operator require the adjustment of the customs duties soon after the original customs clearance, and both parties accept such an adjustment. If, however, a dispute arises, the situation would fall outside of the Customs Code exception that excludes the payment of interest.

105. Such a view is confirmed in the Wortmann judgment, according to which the Customs Code rule excluding interest does not apply to situations where the reimbursement of duties arises from errors in the calculation of duties which were not due to the speed of the customs clearance system. Therefore, it did not apply to the payment of interest in that case in connection with the reimbursement of anti-dumping duties imposed on the basis of an EU regulation which had been partially annulled by the Court.

106. The Netherlands Government claims that the Wortmann judgment excluded from the scope of the Customs Code rule only cases in which the reimbursement happens after the invalidation of the legal basis for payment, which were the circumstances arising in that judgment.

107. However, to my mind, such an interpretation would not be consistent with the justification for that rule as offered in the Wortmann judgment, namely the enabling of the speedy customs clearance system, which Advocate General Campos Sánchez-Bordona called ‘normal circumstances’. ( 56 ) Unless situations which do not fall under ‘normal’ customs clearance operations are excluded from the scope of the Customs Code rule, that rule runs the risk of being found invalid, for not being proportionate to its justificatory aim. Such situations are not just those in which the reimbursement happens after the invalidation of the legal basis for payment.

108. In the present cases, the erroneous assessment by the competent national authorities was not rectified in ‘normal’ speedy customs clearance procedures. The adjustment of the duties was rather the result of the implementation of judgments of the national courts which found that the duties were levied in breach of EU law. Such situations are not covered by the exception envisaged in the Customs Code.

109. Therefore, I consider that Article 241 of the Community Customs Code and Article 116(6) of the Union Customs Code do not exclude the payment of interest in the circumstances of the present cases and that those cases fall within the general rule of the right to payment of interest under the Court’s case-law.

2. Limitations imposed by national law (national rules conditioning the right to payment of interest upon the introduction of an action in court and limiting the payment of interest from the time when such an action is brought)

110. The usual framework under which the analysis of national provisions that limit EU remedial rules are assessed is through the concept referred to as national procedural autonomy. In this Opinion, I do not intend to discuss the appropriateness of the concept of ‘national procedural autonomy’. ( 57 ) It suffices to say that that concept recognises that it is for the Member States to regulate issues of substance and procedure relevant for the exercise of EU remedial rights. That national procedural autonomy exists when there are no pertinent EU rules. However, it is controlled by the principles of equivalence and effectiveness. ( 58 )

111. National rules which limit the effectiveness of rights based on EU law could, however, still be justified, provided that they pursue a legitimate aim in a proportionate way.

112. This ‘procedural rule of reason’, as it was named by scholars, ( 59 ) was formulated by the Court in the judgments of 14 December 1995, van Schijndel and van Veen ( 60 ) and Peterbroeck, ( 61 ) and has been confirmed in subsequent case-law. ( 62 ) The Court has held, with respect to the principle of effectiveness, that every case in which a question arises as to whether a national provision renders the application of EU law impossible in practice or excessively difficult must be analysed by reference to the role of that provision in the procedure, its conduct and its special features, viewed as a whole, before the various national bodies. Therefore, national provisions which pursue some legitimate aim, such as the proper conduct of the procedure or respect for the principle of the rights of the defence or the principle of legal certainty are consistent with the principle of effectiveness in so far as they ensure such a legitimate aim in a proportionate way. That has to be verified in the particular case by the national court concerned.

113. It is in the light of that analytical framework that the national rules which limit the right to payment of interest in the present cases should be assessed.

114. According to the referring court, the national rules applicable in all three cases limit the date from which interest is payable as from the time when proceedings are brought before the competent national court.

115. It should be noted from the outset that there does not seem to be any indications which could give rise to doubts with regard to conformity of those rules with the principle of equivalence. ( 63 )

116. However, as regards the principle of effectiveness, there are, in my view, strong indications that the national rules at issue are not consistent with that principle.

117. Under the Court’s case-law, ( 64 ) EU law requires in principle the payment of interest for the entire period from the date of payment or non-payment of the sums imposed or withheld in breach of EU law to the date of reimbursement or payment thereof. That ensures adequate compensation for losses caused by the unavailability of those sums.

118. Thus, in the Irimie judgment, ( 65 ) the Court held that a system which limits interest to that accruing from the day following the date of the claim for repayment of the tax unduly levied does not satisfy the principle of effectiveness. Furthermore, it should be noted that, in his Opinion in Wortmann, ( 66 ) Advocate General Campos Sánchez-Bordona considered that the same is applicable to the German legislation which is at issue in the present cases.

119. I agree. National rules limiting the payment of interest only from the date from when proceedings are brought before the courts deprive persons of adequate compensation for the entire period of the losses incurred by the fact that they were deprived of the possession of sums unduly levied, as the effective application of the right to payment of interest requires.

120. As indicated by Gräfendorfer, Reyher and Flexi Montagetechnik, in circumstances such as those of the present cases, the period from the payment of the sums unduly levied to the bringing of the action before the courts may take several years, taking into account the administrative complaint procedure which precedes the bringing of an action before the courts. Therefore, the national rules applicable in all three cases do not seem to me to satisfy the requirements of the principle of effectiveness.

121. The referring court indicated an additional element present only in Case C‑415/20 in relation to the payment of interest on the late payment of export refunds. According to that court, it appears that, pursuant to the relevant national law, ( 67 ) in situations of late payment of benefits, interest is payable from the time when proceedings are brought before the courts in which an operator claims payment of such benefits. If, however, late payment is made without judicial proceedings, that is, if the competent national authorities decide to pay the export refunds, then the operator does not have a right to any interest. Therefore, if the operator, as was the situation in that case, only lodged an administrative complaint with the competent national authorities and waited for the decision in a pilot case, after which those authorities paid the export refunds but without interest, that operator is not entitled to interest at all.

122. Such national rules do not, in my view, comply with the principle of effectiveness. It follows from the Court’s case-law that the right to payment of interest exists as a matter of EU law and thus irrespective of national law. Therefore, an operator to whom export refunds were paid late is entitled to the payment of interest. Making such a right dependent on the initiation of judicial proceedings deprives persons, such as the applicant in Case C‑415/20, who did not bring a claim for such refunds before the courts, of the right which they enjoy on the basis of EU law.

123. Even though the national rules at issue, as described by the referring court, curtail the effectiveness of the right to payment of interest based on EU law, this does not preclude, depending on the particular circumstances of the case, such rules from being allowed under EU law. That is possible only provided that such rules are proportionate in relation to important interests of the domestic legal system.

124. However, in the present cases, no information has been put before the Court that would allow an assessment of whether the national rules which limit the right to payment of interest are justified. As far as the national rules conditioning the right to payment of interest with the introduction of an action before the courts are concerned, the referring court mentioned that such rules may be explained by the autonomy of decision-making that belongs to operators, namely, that a decision to await the outcome of a pilot case, rather than to bring judicial proceedings, might be seen as an exercise of such autonomy by which the operator has waived its right to interest. I fail to see the public aim of such rules. Rather, and to the contrary, it seems to me that their effect is an unnecessary increase of judicial proceedings. Nonetheless, in the division of competences between the Court of Justice and the national courts, both functioning as European courts (see points 82 to 84 of this Opinion), it is for the referring court to assess the justifications and proportionality of the national rules at issue.

125. In conclusion, it should be considered that, subject to verification by the referring court, the national rules at issue, by limiting the payment of interest on the reimbursement of the sums unduly levied or paid with delay by the competent national authorities in breach of EU law, do not meet the requirements of the principle of effectiveness.

126. The consequence that flows from such a finding under EU law is that the referring court can either interpret those national rules in the manner which satisfies the effective application of the right to payment of interest, or, should that prove impossible, disapply them in the cases at hand.

VI. Conclusion

127. In the light of the foregoing considerations, I propose that the Court should answer the questions referred for a preliminary ruling by the Finanzgericht Hamburg (Finance Court, Hamburg, Germany) as follows: Case C‑415/20 (1) The requirement under EU law for the Member States to repay, with interest, duties levied in breach of EU law applies where the reason for the repayment is not a finding by the Court of Justice that a provision of EU law has been breached, but that the Court of Justice has interpreted a (sub)heading of the Combined Nomenclature. (2) The principles relating to a claim of interest established by the Court of Justice apply to the payment of export refunds refused by the competent national authorities in breach of EU law. Case C‑419/20 There is an infringement of EU law, which is a condition for entitlement to interest under EU law, as developed by the Court of Justice, where the competent national authorities impose duties pursuant to EU law, but a national court subsequently finds that the factual conditions for the imposition of those duties have not been met. Case C‑427/20 There is an infringement of EU law, which is a condition for entitlement to interest under EU law, as developed by the Court of Justice, where the competent national authorities impose duties in breach of legally valid provisions of EU law and a national court makes a finding of that infringement of EU law.

( 1 ) Original language: English.

( 2 ) OJ 1992 L 302, p. 1 (‘the Community Customs Code’).

( 3 ) OJ 2008 L 145, p. 1.

( 4 ) OJ 2013 L 269, p. 1, and corrigendum, OJ 2013 L 287, p. 90 (‘the Union Customs Code’). According to Articles 287 and 288 thereof, that code entered into force on 30 October 2013 and applies, apart from certain provisions (not including Article 116 thereof), as from 1 May 2016.

( 5 ) Commission Regulation (EC) No 800/1999 of 15 April 1999 laying down common detailed rules for the application of the system of export refunds on agricultural products (OJ 1999 L 102, p. 11). That regulation was repealed and replaced by Commission Regulation (EC) No 612/2009 of 7 July 2009 laying down common detailed rules for the application of the system of export refunds on agricultural products (OJ 2009 L 186, p. 1).

( 6 ) The referring court mentions, in that regard, the judgments of 18 February 2014 of the Finanzgericht Hamburg (Finance Court, Hamburg), 4 K 18/12 and 4 K 264/11.

( 7 ) C‑323/10 to C‑326/10, EU:C:2011:774. That case concerned the interpretation of subheadings 02071210 and 02071290 of Annex I to Commission Regulation (EEC) No 3846/87 of 17 December 1987 establishing an agricultural product nomenclature for export refunds (OJ 1987 L 366, p. 1).

( 8 ) C‑365/15, EU:C:2017:19 (‘the Wortmann judgment’).

( 9 ) Council Regulation (EC) No 91/2009 of 26 January 2009 imposing a definitive anti-dumping duty on imports of certain iron or steel fasteners originating in the People’s Republic of China (OJ 2009 L 29, p. 1). That regulation was repealed by Commission Implementing Regulation (EU) 2016/278 of 26 February 2016 repealing the definitive anti-dumping duty imposed on imports of certain iron or steel fasteners originating in the People’s Republic of China, as extended to imports of certain iron or steel fasteners consigned from Malaysia, whether declared as originating in Malaysia or not (OJ 2016 L 52, p. 24).

( 10 ) See judgment of 16 December 1976, Rewe-Zentralfinanz and Rewe-Zentral (33/76, EU:C:1976:188).

( 11 ) See judgment of 16 December 1976, Comet (45/76, EU:C:1976:191).

( 12 ) See judgment of 9 November 1983, San Giorgio (199/82, EU:C:1983:318).

( 13 ) See judgment of 26 June 1979, McCarren (177/78, EU:C:1979:164).

( 14 ) See judgment of 9 February 1999, Dilexport (C‑343/96, EU:C:1999:59).

( 15 ) See judgment of 2 December 1997, Fantask and Others (C‑188/95, EU:C:1997:580).

( 16 ) See judgment of 8 March 2001, Metallgesellschaft and Others (C‑397/98 and C‑410/98, EU:C:2001:134).

( 17 ) See judgment of 19 July 2012, Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:478).

( 18 ) See judgments of 18 April 2013, Irimie (C‑565/11, EU:C:2013:250), and of 15 October 2014, Nicula (C‑331/13, EU:C:2014:2285).

( 19 ) See judgment of 9 September 2021, Hauptzollamt B (Optional tax reduction) (C‑100/20, EU:C:2021:716).

( 20 ) That case-law started with the judgment of 9 November 1983, San Giorgio (199/82, EU:C:1983:318, paragraph 12). It was confirmed by subsequent case-law, such as the judgment of 8 March 2001, Metallgesellschaft and Others (C‑397/98 and C‑410/98, EU:C:2001:134, paragraph 84), or, more recently, the judgment of 9 September 2021, Hauptzollamt B (Optional tax reduction) (C‑100/20, EU:C:2021:716, paragraph 26).

( 21 ) It might even be claimed that the right to reimbursement was the first remedy based on EU law found by the Court to be inherent in the system as established by the Treaties. The case-law on the right to reimbursement precedes that in which the Court developed other remedies, such as the right to interim relief (starting with the judgment of 19 June 1990, Factortame and Others, C‑213/89, EU:C:1990:257) or the right to damages (starting with the judgment of 19 November 1991, Francovich and Others, C‑6/90 and C‑9/90, EU:C:1991:428). However, the right to reimbursement was not immediately recognised as a remedy based on EU law because the majority of the national legal systems provided for some form of claim in restitution of unduly paid charges. Therefore, it was not immediately clear that EU law contains its own legal basis for reimbursement which does not depend on national law. See, in that regard, Dougan, M., ‘Cutting Your Losses in the Enforcement Deficit: A Community Right to the Recovery of Unlawfully Levied Charges?’, Cambridge Yearbook of European Legal Studies, vol. 1, 1998-1999, p. 233; Ćapeta, T., Sudovi Europske unije. Nacionalni sudovi kao europski sudovi (EU Courts. National Courts as European Courts), Institut za međunarodne odnose, IMO, Zagreb, 2002, p. 109 et seq.

( 22 ) See, for example, judgments of 19 July 2012, Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:478, paragraph 25), and of 9 September 2021, Hauptzollamt B (Optional tax reduction) (C‑100/20, EU:C:2021:716, paragraph 27).

( 23 ) See, for example, judgments of 19 July 2012, Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:478, paragraph 26), and of 9 September 2021, Hauptzollamt B (Optional tax reduction) (C‑100/20, EU:C:2021:716, paragraph 27).

( 24 ) See, in that regard, Opinion of Advocate General Trstenjak in Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:9, points 26 to 30), and Opinion of Advocate General Wathelet in Irimie (C‑565/11, EU:C:2012:803, points 21 to 29).

( 25 ) See, for example, Gazin, F., ‘L’étendue du versement des sommes dues par les États en violation du droit de l’Union européenne : le beurre et l’argent du beurre au service de l’efficacité du droit’, Revue du marché commun et de l’Union européenne, No 571, 2013, p. 475; Schlote, M., ‘The San Giorgio “cause of action”’, British Tax Review, 2014, p. 103; van de Moosdijk, M., Unjust Enrichment in European Union Law, Kluwer, 2018, in particular pp. 68-83; Episcopo, F., ‘The Vicissitudes of Life at the Coalface: Remedies and Procedures for Enforcing Union Law before the National Courts’, in Craig, P. and de Búrca, G. (eds), The Evolution of EU Law, Third edition, Oxford University Press, 2021, p. 275, in particular pp. 290-291.

( 26 ) The referring court mentions, in that regard, the judgments of 27 September 2012, Zuckerfabrik Jülich and Others (C‑113/10, C‑147/10 and C‑234/10, EU:C:2012:591); of 18 April 2013, Irimie (C‑565/11, EU:C:2013:250); and of 18 January 2017, Wortmann (C‑365/15, EU:C:2017:19).

( 27 ) See judgment of 27 September 2012, Zuckerfabrik Jülich and Others (C‑113/10, C‑147/10 and C‑234/10, EU:C:2012:591).

( 28 ) See judgment of 18 April 2013, Irimie (C‑565/11, EU:C:2013:250).

( 29 ) See judgment of 18 January 2017, Wortmann (C‑365/15, EU:C:2017:19).

( 30 ) See judgment of 19 July 2012, Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:478).

( 31 ) For example, in Case C‑419/20, Reyher indicated that it paid the sum of EUR 774000 in 2013, while it was reimbursed only in 2019.

( 32 ) See, for example, Dougan, cited in footnote 21 of this Opinion; Gazin, cited in footnote 25 of this Opinion.

( 33 ) Judgment of 20 October 2011, Danfoss and Sauer-Danfoss (C‑94/10, EU:C:2011:674, paragraph 23).

( 34 ) See, for example, judgments of 19 July 2012, Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:478, paragraph 25), and of 9 September 2021, Hauptzollamt B (Optional tax reduction) (C‑100/20, EU:C:2021:716, paragraph 27).

( 35 ) See, in that regard, van de Moosdijk, cited in footnote 25.

( 36 ) C‑113/10, C‑147/10 and C‑234/10, EU:C:2011:701, points 125 to 129.

( 37 ) C‑47/07 P, EU:C:2008:726, in particular paragraphs 44 to 50.

( 38 ) C‑575/18 P, EU:C:2020:530, in particular paragraphs 81 to 84. See also Opinion of Advocate General Sharpston in Czech Republic v Commission (C‑575/18 P, EU:C:2020:205, points 120 to 129), and Opinion of Advocate General Kokott in Slovakia v Commission and Romania v Commission (C‑593/15 P, C‑594/15 P and C‑599/15 P, EU:C:2017:441, point 108).

( 39 ) In that regard, it is useful to mention case-law in which the Court has allowed the Member States to take into account the concept of unjust enrichment. That case-law arose in circumstances involving national rules limiting the right to reimbursement of sums unduly paid in breach of EU law where the sums had been passed on to other traders or consumers. See, for example, judgment of 27 February 1980, Just (68/79, EU:C:1980:57, paragraphs 26 and 27). That case-law confirms the proposed view that the right to payment of interest under EU law is justified by the need to prevent impoverishment contrary to EU law. A person who passed on unduly charged sums to others would not be impoverished, which is why that person’s right to reimbursement with interest under EU law may be denied.

( 40 ) The reimbursement of taxes, levies and other charges is not the only situation in which EU law envisages the payment of interest. Such interest is, for instance, owed also in the context of claims for damages which result from the breach of EU law. See, for example, judgment of 2 August 1993, Marshall (C‑271/91, EU:C:1993:335, paragraph 31).

( 41 ) See, in that regard, Opinion of Advocate General Campos Sánchez-Bordona in Wortmann (C‑365/15, EU:C:2016:663, point 66).

( 42 ) See judgment of 19 July 2012, Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:478).

( 43 ) See judgment of 9 September 2021, Hauptzollamt B (Optional tax reduction) (C‑100/20, EU:C:2021:716).

( 44 ) See, for example, judgments of 27 February 2018, Associação Sindical dos JuízesPortugueses (C‑64/16, EU:C:2018:117, paragraph 32), and of 16 November 2021, WB and Others (C‑748/19 to C‑754/19, EU:C:2021:931, paragraph 59).

( 45 ) See, for example, Opinion 1/09 (Agreement creating a Unified Patent Litigation System) of 8 March 2011 (EU:C:2011:123, paragraph 69), and judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses (C‑64/16, EU:C:2018:117, paragraph 33).

( 46 ) See, for example, judgments of 25 June 2020, SatCen v KF (C‑14/19 P, EU:C:2020:492, paragraph 61), and of 6 October 2021, Consorzio Italian Management and Catania Multiservizi (C‑561/19, EU:C:2021:799, paragraph 31).

( 47 ) See, in that regard, Opinion 1/09 (Agreement creating a Unified Patent Litigation System) of 8 March 2011 (EU:C:2011:123, paragraph 80).

( 48 ) See judgment of 18 January 2017, Wortmann (C‑365/15, EU:C:2017:19, paragraph 38) (emphasis added).

( 49 ) In his Opinion in Wortmann (C‑365/15, EU:C:2016:663, point 45), Advocate General Campos Sánchez-Bordona offered as one of the possible solutions in that case the finding of the invalidity of the provision of the Customs Code excluding the payment of interest. That was not the solution that he suggested to the Court, given that the provision at issue had an acceptable justification. It is worth noting that the validity of that rule has not been questioned in the present cases.

( 50 ) See judgment of 18 January 2017, Wortmann (C‑365/15, EU:C:2017:19, in particular paragraphs 24 to 32).

( 51 ) The same justification was endorsed by the Commission both in the Wortmann case and in its observations in the present cases.

( 52 ) Judgment of 18 January 2017, Wortmann (C‑365/15, EU:C:2017:19, paragraph 27).

( 53 ) Opinion of Advocate General Campos Sánchez-Bordona in Wortmann (C‑365/15, EU:C:2016:663, point 50).

( 54 ) This symmetry, which excludes the obligation for payment of interest for both the customs authorities, if the customs duties are adjusted downwards, and for the operator, if the customs duties are adjusted upwards, was accentuated as an important element for justification of the rule at issue. See judgment of 18 January 2017, Wortmann (C‑365/15, EU:C:2017:19, paragraphs 29 to 31), and Opinion of Advocate General Campos Sánchez-Bordona in Wortmann (C‑365/15, EU:C:2016:663, points 48 to 52).

( 55 ) There seems to me to be no reason why the considerations set out in the Wortmann judgment, which addressed Article 241 of the Community Customs Code, would not apply to Article 116(6) of the Union Customs Code. See, in that regard, Opinion of Advocate General Campos Sánchez-Bordona in Wortmann (C‑365/15, EU:C:2016:663, point 51, footnote 25).

( 56 ) Opinion of Advocate General Campos Sánchez-Bordona in Wortmann (C‑365/15, EU:C:2016:663, point 52).

( 57 ) But see, in that regard, Kakouris, C.N., ‘Do the Member States Possess Judicial Procedural “Autonomy”?’, Common Market Law Review, vol. 34, 1997, p. 1389; Bobek, M., ‘Why There is No Principle of “Procedural Autonomy” of the Member States’, in de Witte, B. and Micklitz, H.‑W. (eds), The European Court of Justice and the Autonomy of the Member States, Intersentia, 2012, p. 305; Opinion of Advocate General Trstenjak in Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:9, points 23 to 25).

( 58 ) See, in relation to the payment of interest, for example, judgments of 19 July 2012, Littlewoods Retail Ltd and Others (C‑591/10, EU:C:2012:478, paragraphs 27 and 28), and of 23 April 2020, Sole-Mizo and Dalmandi Mezőgazdasági (C‑13/18 and C‑126/18, EU:C:2020:292, paragraph 37). As the Court has indicated in those judgments, in the absence of EU legislation, it is for the domestic legal order of each Member State to lay down the conditions in which such interest must be paid provided that they are not less favourable than those concerning similar claims based on provisions of national law (principle of equivalence) and do not make the exercise of rights conferred by EU law impossible in practice or excessively difficult (principle of effectiveness).

( 59 ) See, in that regard, Prechal, S., ‘Community Law in National Courts: The Lessons from Van Schijndel’, Common Market Law Review, vol. 35, 1998, p. 681, at p. 690. See further, for example, Widdershoven, R., ‘National Procedural Autonomy and General EU Law Limits’, Review of European Administrative Law, vol. 12, 2019, p. 5; Episcopo, cited in footnote 25 of this Opinion.

( 60 ) C‑430/93 and C‑431/93, EU:C:1995:441.

( 61 ) C‑312/93, EU:C:1995:437.

( 62 ) See, for example, judgments of 19 December 2019, Cargill Deutschland (C‑360/18, EU:C:2019:1124, paragraph 51), and of 6 October 2021, Consorzio Italian Management and Catania Multiservizi (C‑561/19, EU:C:2021:799, paragraphs 63 and 64).

( 63 ) Contrary to the arguments put forward by Reyher in Case C‑419/20, the national rules at issue do not seem to me to treat EU law claims less favourably than claims based on national law; the fact that the competent national authorities may contend in the main proceedings that Article 116(6) of the Union Customs Code excludes the payment of interest stems from a possible limitation put on the right to payment of interest by EU law, and not national law.

( 64 ) See, for example, judgment of 18 April 2013, Irimie (C‑565/11, EU:C:2013:250, paragraphs 26 and 28). See also, in that regard, judgment of 23 April 2020, Sole-Mizo and Dalmandi Mezőgazdasági (C‑13/18 and C‑126/18, EU:C:2020:292, paragraph 43).

( 65 ) See judgment of 18 April 2013, Irimie (C‑565/11, EU:C:2013:250, paragraphs 27 and 29). See also, in that regard, judgment of 15 October 2014, Nicula (C‑331/13, EU:C:2014:2285, paragraphs 37 and 38).

( 66 ) C‑365/15, EU:C:2016:663, points 14 and 69 to 73.

( 67 ) The referring court mentions, in that regard, Paragraph 236 of the AO, read in conjunction with Paragraph 14(2) of the MOG.