Opinion of the Advocate General — ECLI:EU:C:2025:851
Date: 2025-10-30
Language of the case: French

Provisional text OPINION OF ADVOCATE GENERAL KOKOTT delivered on 30 October 2025 (1) Case C‑770/23 P European Commission v HB ( Appeal – Public service contracts – Recovery by the Commission of a contractual debt through offsetting against its co-contractor’s claim against it – Contract falling within the jurisdiction of a national court or tribunal – Power of the Commission to adopt a set-off decision – Jurisdiction of the EU Courts to hear an action brought against a set-off decision ) Table of Contents I. Introduction II. Legal framework III. Background to the appeal A. Facts prior to the proceedings before the General Court B. The procedure before the General Court and the judgment under appeal C. Events subsequent to the delivery of the judgment under appeal and the lodging of the present appeal IV. Appeal proceedings and forms of order sought by the parties V. Assessment A. The appeal 1. The continuing purpose of the appeal 2. Substance (a) The possibility of recovering a contested claim by set-off (first ground of appeal) (b) The possibility of recovering a contractual claim falling within the jurisdiction of a national court by way of set-off (second ground of appeal) (1) Set-off decisions in respect of contractual claims are acts open to challenge for the purposes of Article 263 TFEU (2) It is nevertheless possible to adopt a set-off decision to recover a contractual claim falling within the jurisdiction of a national court 3. Conclusion on the appeal B. The action before the General Court C. Interim conclusion VI. Costs A. The costs relating to the appeal proceedings B. Costs relating to the proceedings at first instance VII. Conclusion I. Introduction 1. In accordance with Article 272 TFEU, the Court of Justice of the European Union is to have jurisdiction to give judgment pursuant to any arbitration clause contained in a contract concluded by or on behalf of the European Union, whether that contract be governed by public or private law. Under Article 274 TFEU, save where jurisdiction is conferred on the Court by the Treaties, disputes to which the European Union is a party are not on that ground to be excluded from the jurisdiction of courts or tribunals of the Member States. 2. Therefore, in the absence of an arbitration clause in favour of the EU Courts, disputes relating to contracts concluded by the European Commission fall within the jurisdiction of the national courts. (2) 3. Despite the deceptive simplicity of that division of jurisdiction, the question as to whether a dispute relating to a contract concluded by the Commission should be brought before the EU judicature or those of the national judicature has already been examined by the Court of Justice on numerous occasions. (3) 4. In that context, the Court held, in the judgment in ADR Center v Commission (‘the judgment in ADR’), (4) that the Commission may only exercise its power to make its decisions on the recovery of contractual debts enforceable, within the meaning of Article 299 TFEU, if the contract concerned contains an arbitration clause in favour of the EU judicature. 5. Such an enforcement decision constitutes an act open to challenge by an action for annulment under Article 263 TFEU, in the context of which the EU judicature must examine the merits of the claim thus recovered. Accordingly, the adoption of such a decision for the recovery of a debt arising under a contract falling within the jurisdiction of a national court would remove the dispute from the court having jurisdiction and circumvent the division of jurisdiction established by the Treaty. (5) 6. Does such a restriction also exist where the Commission recovers a contractual claim falling within the jurisdiction of a national court, not by adopting an enforcement decision, but through offsetting? In other words, is the Commission prevented from recovering, through the mechanism of offsetting, a debt it claims pursuant to a contract that does not contain an arbitration clause in favour of the EU judicature? 7. In the judgment under appeal, (6) the General Court held that to be the case. According to the General Court, a set-off decision, like a enforcement decision within the meaning of Article 299 TFEU, constitutes a challengeable act pursuant to Article 263 TFEU. However, a claim arising from a contract which does not contain an arbitration clause falls within the jurisdiction of a national court, for the purpose of examining its merits. Accordingly, the adoption of a set-off decision in order to recover such a debt would also constitute a circumvention of the division of jurisdictions established by the Treaty. (7) 8. In the present appeal proceedings, the Court of Justice is called upon to determine the merits of that solution. 9. Before it can address that issue, the Court will have to determine whether the present appeal retains its purpose. That question arises because HB’s claim against the Commission, with which the latter carried out the set-off at issue, no longer exists, which deprives the set-off decision contested at first instance of its purpose. II. Legal framework 10. The present dispute is governed by the provisions of Regulation (EU, Euratom) 2018/1046 on the financial rules applicable to the general budget of the Union (‘the 2018 Financial Regulation’). (8) 11. Article 98 of the 2018 Financial Regulation, entitled ‘Establishment of amounts receivable’, provides, inter alia: ‘1. In order to establish an amount receivable, the authorising officer responsible shall: (a) verify that the debt exists; (b) determine or verify the reality and the amount of the debt; and (c) verify the conditions according to which the debt is due. The establishment of an amount receivable shall constitute recognition of the right of the Union in respect of a debtor and establishment of entitlement to demand that the debtor pay the debt. 2. Any amount receivable that is identified as being certain, of a fixed amount and due shall be established by a recovery order by which the authorising officer responsible instructs the accounting officer to recover the amount. It shall be followed by a debit note sent to the debtor, except for the cases where a waiver procedure is carried out immediately in accordance with the second subparagraph of paragraph 4. Both the recovery order and the debit note shall be drawn up by the authorising officer responsible. The authorising officer shall send the debit note immediately after establishing the amount receivable and at the latest within a period of five years from the time when the Union institution was, in normal circumstances, in a position to claim its debt … 3. To establish an amount receivable the authorising officer responsible shall ensure that: (a) the amount receivable is certain, meaning that it is not subject to any condition; (b) the amount receivable is fixed, expressed precisely in cash terms; (c) the amount receivable is due and is not subject to any payment time; … 4. The debit note shall be to inform the debtor that: (a) the Union has established the amount receivable; …’ 12. The third subparagraph of Article 101(1) of the 2018 Financial Regulation provides that ‘the accounting officer shall recover amounts due to the budget by offsetting them in accordance with Article 102’. 13. Article 102 of the 2018 Financial Regulation, which is entitled ‘Recovery by offsetting’, is worded as follows: ‘1. Where the debtor has a claim on the Union, or on an executive agency when it implements the budget, that is certain within the meaning of Article 98(3), point (a), of a fixed amount and due relating to a sum established by a payment order, the accounting officer shall, after expiry of the deadline referred to in Article 98(4), first subparagraph, point (b), recover established amounts receivable by offsetting. In exceptional circumstances, where it is necessary to safeguard the financial interests of the Union and where the accounting officer has justified grounds to believe that the amount due to the Union would be lost, the accounting officer may recover by offsetting before the expiry of the deadline referred to in Article 98(4), first subparagraph, point (b). The accounting officer may also recover by offsetting before the expiry of the deadline referred to in Article 98(4), first subparagraph, point (b), when the debtor agrees. 2. Before proceeding with any recovery in accordance with paragraph 1 of this Article, the accounting officer shall consult the authorising officer responsible and inform the debtors concerned, including of the means of redress in accordance with Article 134. … 3. The offsetting referred to in paragraph 1 shall have the same effect as a payment and discharge the Union for the amount of the debt and, where appropriate, of the interest due.’ 14. Article 103 of the 2018 Financial Regulation is entitled ‘Recovery procedure failing voluntary payment’ and provides as follows: ‘1. Without prejudice to Article 102, if the full amount has not been recovered by the deadline referred to in Article 98(4), first subparagraph, point (b), the accounting officer shall inform the authorising officer responsible and shall without delay launch the procedure for effecting recovery by any means offered by the law, including, where appropriate, by enforcement of any guarantee lodged in advance. 2. Without prejudice to Article 102, where the recovery method referred to in paragraph 1 of this Article cannot be used and the debtor has failed to pay in response to a letter of formal notice sent by the accounting officer, the accounting officer shall effect recovery by enforcement of a decision secured either in accordance with Article 100(2) or by legal action.’ III. Background to the appeal A. Facts prior to the proceedings before the General Court 15. The background to the dispute is set out in paragraphs 14 to 37 of the judgment under appeal and may be summarised as follows. 16. On 24 October 2007, the European Union, represented by the European Agency for Reconstruction (EAR), launched a call for tenders with a view to concluding the CARDS contract, namely a service contract for the provision of technical assistance services to the High Judicial Council in Serbia. 17. On 10 June 2008, the CARDS contract was awarded to the consortium led by HB. The corresponding contract (‘the CARDS contract’) was signed on 30 July 2008 for a maximum value of EUR 1 999 125. The contract stipulated, inter alia, that any dispute arising therefrom or relating thereto was within the jurisdiction of the courts of Brussels (Belgium). (9) 18. Following a finding of irregularities by the European Anti-Fraud Office (OLAF), on 15 October 2019 the Commission adopted Decision C(2019) 7319 final. By that decision (‘the CARDS recovery decision’), it found that the CARDS payments, amounting to EUR 1 197 055.86, had been unduly paid and should be recovered from HB. 19. On 19 November 2019, HB brought two actions before the General Court challenging, inter alia, the legality of the CARDS recovery decision. Those actions were registered under case numbers T‑795/19 and T‑796/19 respectively. 20. On 7 February 2020, HB brought an action against the European Union, represented by the Commission, before the tribunal de première instance francophone de Bruxelles (Brussels Court of First Instance (French-speaking), Belgium). In essence, it sought a declaration that the European Union was not entitled to terminate the CARDS contract. In the alternative, it sought an order requiring the European Union to pay contractual damages equivalent to the amount of the contract. 21. On 19 February 2021, the tribunal de première instance francophone de Bruxelles (Brussels Court of First Instance (French-speaking)) delivered a judgment by which it declared that it had the requisite jurisdiction to hear and determine the action brought by HB. However, it decided to stay the proceedings on the substance pending the final decisions in Cases T‑795/19 and T‑796/19. 22. By its judgments of 21 December 2021 in HB v Commission (10) and HB v Commission (11) (together, ‘the judgments in T‑795/19 and T‑796/19, HB v Commission’), the General Court, inter alia, dismissed the actions as inadmissible in so far as they sought annulment of the CARDS recovery decision. In addition, it ordered the Commission to pay the costs, including those relating to the interlocutory proceedings brought by HB. 23. By letter of 31 March 2022, the Commission indicated its agreement with the amount of costs claimed from it in respect of the judgments in Cases T‑795/19 and T‑796/19, namely a total sum of EUR 19 904.76. However, it indicated its intention to pay that sum by offsetting, in so far as, in essence, the debt arising from the CARDS recovery decision remained due. 24. On 13 May 2022, the Commission adopted a decision (‘the decision at issue’) by which it offset HB’s claim against it for the costs in Cases T‑795/19 and T‑796/19 and the claim which the Commission stated it had against HB under the CARDS recovery decision in the amount of EUR 1 197 055.86. B. The procedure before the General Court and the judgment under appeal 25. By document lodged at the Registry of the General Court on 18 July 2022, HB brought an action for the annulment of the decision at issue and for an order that the Commission pay compensation for its material damage. 26. By the judgment under appeal, the General Court annulled the decision at issue (point 1 of the operative part), dismissed the action as to the remainder (point 2 of the operative part) and ordered HB and the Commission each to bear their own costs (point 3 of the operative part). C. Events subsequent to the delivery of the judgment under appeal and the lodging of the present appeal 27. By judgment of 26 September 2024, Commission v HB, in the Joined Cases C‑160/22 P and C‑161/22 P, the Court of Justice set aside the judgments in Cases T‑795/19 and T‑796/19, referred those cases back to the General Court and reserved the costs (‘the judgment in joined cases C‑160/22 P and C‑161/22 P, Commission v HB’). (12) IV. Appeal proceedings and forms of order sought by the parties 28. By means of its application of 13 December 2023, rectified on 15 December 2023, the Commission brought an appeal against the judgment under appeal. 29. The Commission contends that the Court of Justice should: – set aside points 1 and 3 of the operative part of the judgment under appeal; – give final judgment in the matter, in accordance with Article 61 of the Statute of the Court of Justice of the European Union, by dismissing the action for annulment of the decision at issue brought by HB at first instance; – order HB to pay the costs of the present proceedings before the Court of Justice and of the proceedings before the General Court. 30. HB claims that the Court of Justice should: – dismiss the appeal brought by the Commission; – order the Commission to pay all the costs. 31. By application under Article 149 of the Rules of Procedure of the Court of Justice, sent to the parties on 21 October 2024, the Court asked the parties to express their views on whether the present appeal had become devoid of purpose following delivery of the judgment in joined cases C‑160/22 P and C‑161/22 P, Commission v HB. The parties complied with that request within the prescribed period. 32. In accordance with Article 76(2) of the Rules of Procedure, the Court did not consider it necessary to hold a hearing. V. Assessment 33. The present dispute requires consideration, first, of the appeal (A) and, second, of the action before the General Court (B). A. The appeal 34. Before addressing the substance of the present appeal (2), I shall examine whether that appeal retains its purpose despite the fact that the decision at issue challenged at first instance has become devoid of purpose (1). 1. The continuing purpose of the appeal 35. As a preliminary point, it is useful to recall that, by means of a set-off operation, a debtor (in the present case, the Commission) against whom a creditor (in the present case, HB) has a ‘principal claim’ or ‘claim constituting a liability’ offsets that claim against a ‘counterclaim’ or ‘claim constituting an asset’ which the debtor itself has against the creditor of the principal claim. In other words, instead of paying to its creditor the amount of the principal claim, the debtor deducts that amount from the amount of the counterclaim, in order to avoid a back-and-forth exchange of two disbursements between the same persons. 36. Set-off is therefore a particular method of extinguishing a debtor’s obligations and, at the same time and conversely, a method of recovering claims which the debtor in turn claims to have against its creditor. (13) 37. In the present case, as stated in points 22 to 24 of the present Opinion, first, the principal claim owed by the Commission to HB amounted to EUR 19 904.76 and arose from the costs which the General Court had ordered the Commission to pay in Cases T‑795/19 and T‑796/19, HB v Commission. Second, the counterclaim on which the Commission relied against HB and which it partially recovered by the decision at issue amounted to EUR 1 197 055.86 and consisted of the amount which the Commission was claiming from HB in respect of the CARDS contract. 38. As mentioned in point 27 of the present Opinion, by the judgment in joined cases C‑160/22 P and C‑161/22 P, Commission v HB, the Court of Justice set aside the judgments in T‑795/19 and T‑796/19, HB v Commission, referred those cases back to the General Court and reserved the costs. Accordingly, the Commission is no longer liable to HB for the amount of those costs, with the result that the principal claim no longer exists. 39. Consequently, as the Commission acknowledged in its reply to the Court of Justice’s questions, the decision at issue challenged at first instance has become devoid of purpose and must be withdrawn. 40. Moreover, in the judgment in joined cases C‑160/22 P and C‑161/22 P, Commission v HB, the Court of Justice held that the CARDS recovery decision was to be classified as a challengeable act for the purposes of Article 263 TFEU and that the General Court had wrongly held that it fell within the framework of contractual relationships. The counterclaim recovered by the Commission from HB in the decision at issue therefore falls within the jurisdiction of the General Court. It follows that the solution adopted in the judgment in ADR, which concerns the recovery of a contractual debt falling within the jurisdiction of a national court and which forms the basis of the solution adopted in the judgment under appeal, is no longer relevant in the present case. 41. Nevertheless, the Commission argues that the present appeal has not become devoid of purpose, in particular because the Court of Justice must clarify whether the solution adopted by the General Court in the judgment under appeal is valid with a view to the adoption of future decisions to recover debts through set-off, where those debts arise from contracts which do not contain arbitration clauses in favour of the EU judicature. 42. In those circumstances, it must be borne in mind that, according to the settled case-law of the Court, the purposes of the action must, like the interest in bringing proceedings, continue until the final decision, failing which there will be no need to adjudicate. (14) 43. Moreover, it follows from the second and third paragraphs of Article 56 of the Statute of the Court of Justice of the European Union that privileged applicants such as the Commission do not have to show any interest in order to bring an appeal. (15) However, a pending case can be decided only if the points of law raised are not purely hypothetical as a result of the disappearance of the subject matter of the proceedings. (16) Privileged applicants therefore do not enjoy an unrestricted possibility of appealing against the judgments of the General Court before the Court of Justice, (17) nor is it true to say that they have no obligations at all concerning the continued existence of the subject matter of the proceedings. (18) 44. Thus, it is not for the Court of Justice, in the context of the appeal, to take the opportunity to discuss general, hypothetical questions or to deliver a ‘law lecture’. (19) Consequently, the Court refuses to rule on an appeal if the judgment it would give would only be of interest for similar hypothetical cases in the future. (20) 45. Nevertheless, when assessing the interest of non-privileged applicants in bringing proceedings, the Court accepts that, in certain circumstances, such applicants may retain an interest in seeking the annulment of an act repealed in the course of proceedings, in order to induce the author of the contested act to make suitable amendments in the future, and thereby avoid the risk that the unlawfulness alleged in respect of that act will be repeated. (21) Such an interest may continue to exist in particular where it is foreseeable that the institution concerned will, in the short or medium term, adopt new acts based precisely on the legal interpretation called into question by the applicant. (22) 46. Such reasoning must apply a fortiori when determining whether the subject matter of a dispute continues to exist where, as in the present case, the appeal has been brought by a privileged applicant who does not have to demonstrate an interest in bringing proceedings. 47. As mentioned in point 7 of the present Opinion, in the judgment under appeal the General Court held that, in a case such as the present, in which the counterclaim recovered by offsetting arises from a contract that does not contain an arbitration clause in favour of the EU judicature, the Commission does not have the power to use that method of recovery. 48. As the Commission stated in its written observations, it follows that, by virtue of the state of the law determined by the grounds of the judgment under appeal, to which it is required to have regard, (23) it can no longer use set-off in order to recover the debts which it claims against contracting parties to whom it is bound by contracts that do not contain an arbitration clause in favour of the EU judicature. However, the Commission has demonstrated, with figures to support its case, that such claims are very numerous and represent a considerable budgetary item. 49. It follows that the fact that the decision at issue annulled by the operative part of the judgment under appeal has become devoid of purpose does not remove the consequences which the solution adopted in the grounds of that judgment entails for the Commission (24) and, more broadly, for the EU legal order. The fact that the decision has become devoid of purpose does not also denude of purpose the legal assessment on which the operative part of the judgment under appeal is based, (25) that judgment being the subject of the present appeal proceedings. If those proceedings were to result in a finding that there is no need to adjudicate, the solution, contained in the grounds, which constitute the essential basis for the operative part of the judgment under appeal, would therefore acquire the force of res judicata. (26) 50. In those circumstances, it would be contrary not only to the principles of legal certainty and of the protection and sound management of the EU’s finances, but also to the principles of procedural economy and of the sound administration of justice, to consider that the present appeal has become devoid of purpose and to oblige the Commission to seek clarification of the state of the law concerning the set-off of contractual claims by bringing further appeal proceedings. 51. Nor, in any event, does it appear that the fact that the decision at issue is now devoid of purpose has put an end to the dispute between the parties and that, therefore, the appeal has become devoid of purpose on that ground. (27) 52. It follows that, without prejudice to the fact that the object of the proceedings at first instance has become devoid of purpose (see points 105 and 106 of the present Opinion), the present appeal has not become devoid of purpose and, therefore, its substance should be addressed. 2. Substance 53. According to the Commission, the General Court’s reasoning in the judgment under appeal is vitiated by errors of law in two respects. 54. First, the Commission criticises the General Court for having wrongly held that it could not recover by way of set-off a contractual claim whose validity was being contested before the competent national court (a). 55. Second, the Commission submits that the General Court erred in law by treating set-off decisions in the same way as enforcement decisions and by applying to them the considerations set out in the judgment in ADR (b). (a) The possibility of recovering a contested claim by set-off (first ground of appeal) 56. In its first ground of appeal, the Commission submits that the General Court erred in law in paragraphs 60 and 61 of the judgment under appeal. The Commission argues that the General Court confused the assessment of whether the claim is certain, of a fixed amount and due with the examination of whether it is well founded, and wrongly held that a dispute is a factor to be taken into account in assessing whether the claim is certain, of a fixed amount and due. 57. In the paragraphs referred to above, the General Court held that, when it had adopted the decision at issue, the Commission had failed to recognise the division of powers between the EU judicature and the national courts to rule on the legality of a set-off relating to a contractual claim which had been challenged before a national court, which alone had jurisdiction to determine whether that claim was well founded and, more generally, whether it was certain, of a fixed amount and due, allowing it to be taken into account for the purposes of set-off. (28) 58. As the Commission rightly notes, it does indeed follow from that reasoning that the General Court must have implicitly considered that whether or not a claim was disputed was a factor to be taken into account when assessing whether that claim was certain, of a fixed amount and due within the meaning of the provisions of the 2018 Financial Regulation. 59. That interpretation does not stand up to an examination of the relevant provisions of that regulation in the light of their wording, structure and objective. 60. First, the establishment of an amount receivable constitutes recognition of the right of the European Union in respect of a debtor and establishment of entitlement to demand that the debtor pay the debt (second subparagraph of Article 98(1) of the 2018 Financial Regulation). In order to establish an amount receivable, the authorising officer responsible is to ensure, inter alia, that (a) the amount receivable is certain, meaning that it is not subject to any condition, (b) the amount receivable is fixed, expressed precisely in cash terms, and (c) the amount receivable is due and is not subject to any payment time (Article 98(3)(a) to (c) of that regulation). 61. Second, the authorising officer responsible is to establish any amount receivable that is identified as being certain, of a fixed amount and due by a recovery order by which the officer instructs the accounting officer to recover the amount. That recovery order is to be followed by a debit note sent to the debtor, informing the latter of the establishment of the amount receivable and of the deadline for payment (first subparagraph of Article 98(2), first subparagraph of Article 98(4) and Article 100(1) of the 2018 Financial Regulation). 62. Third, unless he or she decides to cancel it in whole or in part, the authorising officer responsible may waive recovery of an established amount receivable only in duly justified cases, where recovery is impossible or disproportionate (Article 101(2) to (6) of the 2018 Financial Regulation). 63. Fourth and lastly, where the debtor has a claim on the Union, the accounting officer is to recover the established amount receivable by offsetting, after giving the debtor the opportunity to submit observations (third subparagraph of Article 101(1), Article 102(1), first subparagraph of Article 102(2) and Article 133 of the 2018 Financial Regulation). 64. A combined reading of those provisions reveals that the certainty of the claim refers only to the fact that it is not subject to any condition (point 60 above) and should not be confused with its uncontested nature. (29) 65. Thus, the certainty of a claim is determined and the recovery order drawn up even before the debtor is informed of the establishment of that amount receivable by the debit note, which may give rise to a challenge (point 61 above). It is true that the accounting officer must give the debtor the opportunity to submit observations before recovering the established amount receivable by offsetting (point 63 above). However, the accounting officer cannot waive recovery of an established amount receivable, even if it is contested, unless that accounting officer decides to cancel it (point 62 above). 66. Consequently, the uncontested nature of a claim is not a condition for establishing that amount receivable and for recovering it by offsetting. On the contrary, where an amount receivable has been established, the authorising officer and the accounting officer responsible may not waive recovery by offsetting. 67. That is, moreover, consistent with the objective of the 2018 Financial Regulation, which consists of the protection of the financial interests and the sound management of the EU budget, which are essential for the functioning of the EU. (30) 68. The General Court was therefore right to hold in cases prior to the present case that a challenge to a claim did not preclude recourse to set-off in order to recover it. (31) 69. It follows that the General Court was wrong to base its reasoning, in paragraphs 60 and 61 of the judgment under appeal, implicitly but necessarily, on the consideration that a challenge to a claim established by the European Union would prevent recovery of that claim through set-off. The Commission’s first ground of appeal is therefore well founded and must be upheld. (b) The possibility of recovering a contractual claim falling within the jurisdiction of a national court by way of set-off (second ground of appeal) 70. In its second ground of appeal, the Commission submits that the General Court committed an error in law in finding that the adoption of a set-off decision in order to recover a contractual claim falling within the jurisdiction of a national court would lead to a circumvention of the division of jurisdiction established by primary law. Even if such a set-off decision constituted an act open to challenge before the EU judicature, it cannot, in that regard, be treated in the same way as an enforcement decision within the meaning of Article 299 TFEU, such as that which was the subject of the judgment in ADR. 71. In order to assess those complaints, it is necessary, in the first place, to confirm that the General Court was right to characterise set-off decisions as acts open to challenge for the purposes of Article 263 TFEU (paragraphs 52 and 54 of the judgment under appeal) (1). 72. In the second place, I shall assess whether the Commission nonetheless has the power to adopt such decisions in order to recover contractual claims falling, for the purpose of examining their merits, within the jurisdiction of a national court (2). (1) Set-off decisions in respect of contractual claims are acts open to challenge for the purposes of Article 263 TFEU 73. According to the case-law, where there is a contract between the applicant and one of the institutions, an action may be brought before the EU judicature on the basis of Article 263 TFEU only where the contested measure aims to produce binding legal effects falling outside of the contractual relationship between the parties and which involve the exercise of the prerogatives of a public authority conferred on the contracting institution in its capacity as an administrative authority. (32) 74. It is true that set-off is a mechanism which is commonly used in civil law between private persons who do not have the prerogatives of a public authority. (33) However, the adoption of a set-off decision, under the regime established by the 2018 Financial Regulation, in order to recover a contractual debt, is an act which falls outside of the contractual relationship between the parties and which involves the exercise of the prerogatives of a public authority conferred on the contracting institution in its capacity as an administrative authority. 75. First, where the Commission offsets a counterclaim which it asserts it has against its co-contractor against a principal claim that the latter has against it by virtue of another contractual or unilateral relationship, (34) that decision produces binding legal effects which go beyond the contractual relationship from which the counterclaim arises. 76. Second, the adoption of such a decision involves the exercise of the prerogatives of a public authority conferred on the Commission in its capacity as an administrative authority. On that basis, the binding legal effects of such a decision go beyond any contractual relationship between the parties, irrespective of whether or not the principal claim and counterclaim which are the subject of the set-off decision arise from the same contract. 77. Indeed, as explained in the ADR case, the binding legal effects of a decision adopted under the prerogatives of a public authority conferred on the contracting institution in its capacity as an administrative authority are never confined to the contractual relationship between the parties alone. Such a decision also still has non-contractual legal effects due to the very fact that those effects are based on a general, non-contractual prerogative of the contracting institution that falls outside of the contractual framework. (35) 78. As regards set-off decisions, they fall within the scope of the exercise of such prerogatives of a public authority, essentially, for two reasons. 79. First, the adoption of a set-off decision is an exercise of public authority because the Commission is required, as explained in points 64 to 66 of the present Opinion, to adopt such a decision even if the claim being recovered is disputed. 80. Second, and more importantly, unlike relationships between private parties under civil law, the Commission’s co-contractor cannot raise a set-off against that institution if the Commission disputes the claim made against it. The 2018 Financial Regulation does not provide for any set-off mechanism allowing the co-contractor to effect a set-off in such circumstances. 81. In addition, it follows from a combined reading of Article 102(1) and Article 111(3) to (5) of the 2018 Financial Regulation that a co-contractor of the Commission may have a claim on the Union that is certain, of a fixed amount and due only if the corresponding sum has been established by a payment order. Such a payment order is only issued where the authorising officer responsible has previously accepted that an item of expenditure is to be charged to the budget, after having checked, inter alia, that the conditions set in the legal commitment providing for that expenditure have been met. Therefore, if the Commission considers that an item of expenditure which a co-contractor is claiming from it is not justified, no such payment order will be issued and the co-contractor will therefore not have a claim that is certain, of a fixed amount and due that may be taken into account in a set-off operation. 82. It follows that the General Court was right to hold, in the context of settled case-law, that set-off decisions adopted by the Commission are acts open to challenge before the EU judicature by way of an action for annulment under Article 263 TFEU. (36) (2) It is nevertheless possible to adopt a set-off decision to recover a contractual claim falling within the jurisdiction of a national court 83. In the context of the present appeal, it is true that the Commission agrees with the view expressed by the General Court in the judgment under appeal that a set-off decision in respect of a contractual claim falling within the jurisdiction of a national court is an act open to challenge before the EU judicature under Article 263 TFEU. However, it takes the view that the General Court erred when it inferred from that finding that the adoption of such a decision gives rise to a circumvention of the division of jurisdiction established by the Treaty. The logic underlying the judgment in ADR cannot be transposed in such a way to set-off decisions. 84. In the judgment in ADR, the Court of Justice clarified that the Commission does not have the power to adopt enforcement decisions within the meaning of Article 299 TFEU in order to recover contractual claims falling within the jurisdiction of the national courts. Therefore, the Commission cannot adopt such decisions to recover claims arising from contracts which do not contain an arbitration clause in favour of the EU judicature. (37) 85. The reason for that restriction lies not only in the fact that an enforcement decision within the meaning of Article 299 TFEU constitutes a challengeable act under Article 263 TFEU, but also, and above all, in the fact that, in the context of such an action, the EU judicature must examine the merits of the claim. 86. As I stated in the ADR case, under the fourth paragraph of Article 299 TFEU, the enforcement of an enforcement decision may be suspended only by a decision of the Court of Justice, while the courts of the countries concerned have jurisdiction only over complaints that enforcement is being carried out in an irregular manner. Furthermore, the Rules of Procedure of both the General Court and the Court of Justice provide that applications to suspend the enforcement of any measure, submitted pursuant to Article 299 TFEU, are admissible only in connection with an action before the General Court or the Court of Justice. (38) 87. In those circumstances, the right to an effective judicial remedy requires that, when such an action is brought before it, the EU judicature must also examine the merits of the claim. (39) Otherwise, the enforced recovery of a claim could take place without any judicial oversight. 88. The adoption of an enforcement decision for the recovery of a contractual claim falling within the jurisdiction of a national court would therefore amount to removing the examination of the merits of that claim from the competent national court and, in so doing, to circumventing the division of jurisdiction established by the Treaty. 89. As the Commission rightly submits, however, that reasoning does not apply to set-off decisions within the meaning of Article 102 of the 2018 Financial Regulation, such as the decision at issue which is the subject of the judgment under appeal. 90. Thus, it is true that Article 102(3) of the 2018 Financial Regulation provides that the offsetting referred to in paragraph 1 of that article is to have the same effect as a payment and is to discharge the Union for the amount of the debt and, where appropriate, of the interest due. 91. However, in the event of recovery of a contractual claim submitted to a national court for examination of its merits on account of the absence of an arbitration clause in the contract concerned, a teleological reduction of that provision should be carried out. In other words, it should be interpreted restrictively as meaning that the set-off does not discharge the Union from the amount of the debt (the principal claim). It discharges it only from the obligation to pay the principal claim pending the outcome of the examination of any challenge to the validity of the counterclaim recovered by way of set-off. 92. As I indicated in the ADR case, in those circumstances, a set-off decision has only practical and not legal effect in relation to the counterclaim recovered. (40) Such a decision may, of course, become final, either because the co-contractor does not challenge it before the EU judicature, or because that judicature confirms its validity in a judgment which has acquired the force of res judicata. However, that does not prejudge the question of the merits of the counterclaim which is the subject of that decision. The latter cannot confer definitive legal force on the establishment of that claim. The conditions under which the establishment of that claim acquires legal force are, on the contrary, determined by the statutory and contractual rules to which it is subject, and are to be assessed by the competent court. 93. In those circumstances, the review carried out by the EU judicature hearing an action for annulment of a set-off decision adopted under Article 102 of the 2018 Financial Regulation is limited to verifying the conditions laid down by that regulation for the adoption of such a decision (see points 60 to 66 of the present Opinion). However, neither that review nor the force of res judicata of the judgment thus delivered can extend to the merits of the contractual counterclaim recovered. (41) That issue does not fall within the jurisdiction of the EU judicature on account of the absence of an arbitration clause in the contract concerned. (42) 94. Consequently, that judicial review conducted by the EU judicature into the set-off decision does not result in a circumvention of the division of jurisdiction established by primary law. Unlike in the case of enforcement decisions, which are the subject of the judgment in ADR, in the case of set-off decisions it is therefore conceivable that the court reviewing the legality of the set-off decision and the court with jurisdiction to determine whether the claim asserted by the Commission and recovered by means of that set-off is well founded may not be the same. 95. At the same time, the restriction of the review carried out by the EU judicature to the conditions laid down by the 2018 Financial Regulation for the adoption of a set-off decision, which do not include verification of the merits of the counterclaim concerned, does not constitute a breach of the right to an effective judicial review. That follows from the fact, stated in points 91 and 92 above, that the set-off decision does not have the effect of conferring a definitive character on the establishment of the counterclaim. It merely has the effect of deferring the disbursement of the co-contractor’s principal claim until the outcome of the proceedings before the competent national court to determine the validity of the counterclaim. 96. As the Commission rightly acknowledges, if the competent national court were to find that such a claim did not exist, the Commission would naturally be required to pay to its co-contractor the amount withheld from the principal debt, if necessary together with interest. (43) As the General Court has previously recognised in related circumstances, it could also, to the extent of the possibilities conferred on it in that regard by its Rules of Procedure, stay the action against the set-off decision pending the decision of the national court on the merits of the claim concerned. (44) 97. Admittedly, the adoption of the set-off decision, in so far as it recovers, in practice, the amount of the counterclaim sought by the Commission (as a result of the non-payment of the co-contractor’s principal claim), reverses the burden of bringing the matter before the court with jurisdiction to have the question of the merits of the counterclaim settled. Thus, it is not for the Commission to bring the matter before that court in order to have the merits of its alleged claim examined and to obtain an enforcement decision in order to recover it. Instead, it is for the co-contractor to bring the matter before the court in order to have the validity of the claim made by the Commission examined and, where appropriate, to obtain a judgment requiring the Commission to pay the amount of the principal claim retained under the set-off decision. 98. Nevertheless, the fact that the co-contractor is thus placed at a disadvantage vis-à-vis the Commission by virtue of the Commission being afforded that facility when recovering its claims is justified by the need to protect the financial interests of the European Union. (45) As I have previously indicated in the ADR case, it would be inconsistent with that principle to require the Commission to pay EU funds to a debtor who is in default, insolvent or simply unwilling to pay. (46) 99. It is for that reason that, under the 2018 Financial Regulation, offsetting is the mandatory priority method of recovering amounts receivable by the Union, ahead of any other recovery method. (47) Thus, as the General Court has correctly noted in other cases, the accounting officer may not refrain from using offsetting where the debtor has a debt to the European Union and has not complied voluntarily. (48) However, if it has not been possible to recover the debt by offsetting or by enforcement of any guarantee lodged in advance, the accounting officer may effect recovery of the debt, either through the adoption of an enforcement decision or through a decision secured by legal action. (49) 100. It is therefore also in that respect that enforcement decisions for the purposes of Article 299 TFEU, which are the subject of the judgment in ADR, differ from set-off decisions, which are the subject of the present case. In so far as the former are an option available to the Commission in the same way as securing an order through the courts, it is justified that their use be restricted on the basis of Articles 272 and 274 TFEU (see points 1 to 5 of the present Opinion). Conversely, since recourse to the latter is mandatory and not optional, their effects cannot confer legal force on the establishment of an amount receivable which, under those provisions of primary law, is a matter for a national court as regards the examination of its merits. 101. It follows from those considerations that the General Court erred in finding that, in the circumstances of the present case, the Commission did not have the power to adopt the decision at issue on the basis of the solution adopted in the judgment in ADR. The Commission’s second ground of appeal is therefore also well founded and must be upheld. 3. Conclusion on the appeal 102. It follows from the foregoing examination that the General Court’s reasoning underlying point 1 of the operative part of the judgment under appeal is vitiated by errors of law. That judgment must therefore be set aside in so far as it annulled the decision at issue in point 1 of its operative part. B. The action before the General Court 103. In accordance with the first paragraph of Article 61 of the Statute of the Court of Justice of the European Union, if the decision of the General Court is set aside, the Court of Justice may itself give final judgment in the matter, where the state of the proceedings so permits. 104. That applies in the case at hand. 105. As stated in points 37 to 39 of the present Opinion, in so far as HB’s principal claim against the Commission which the Commission offset against its alleged counterclaim against HB under the CARDS contract no longer exists, the decision at issue has become devoid of purpose. 106. Therefore, there is no longer any need to adjudicate on the action for annulment of that decision brought by HB before the General Court. C. Interim conclusion 107. It follows from all of the foregoing that the judgment under appeal should be set aside in so far as it annulled the decision at issue in point 1 of its operative part, and that the Court should give final judgment in the matter and find that there is no longer any need to adjudicate on the action for annulment of the decision at issue brought by HB before the General Court. VI. Costs A. The costs relating to the appeal proceedings 108. Under Article 184(2) of the Rules of Procedure, where the appeal is unfounded or where the appeal is well founded and the Court of Justice itself gives final judgment in the case, the Court is to make a decision as to costs. Under Article 138(1) of those rules, applicable to appeal proceedings by virtue of Article 184(1) of those rules, the unsuccessful party is to be ordered to pay the costs if they have been applied for in the successful party’s pleadings. 109. As HB has been unsuccessful in the present appeal proceedings and the Commission has asked for costs, HB must be ordered to pay the costs relating to the appeal proceedings. B. Costs relating to the proceedings at first instance 110. Article 149 of the Rules of Procedure stipulates that the Court shall give a decision as to costs if it declares that the action has become devoid of purpose and that there is no longer any need to adjudicate on it. Pursuant to Article 142 of the Rules of Procedure, where a case does not proceed to judgment the costs are to be at the discretion of the Court. 111. In the present case, it is apparent that there is no longer any need to adjudicate on the action for annulment of the decision at issue brought by HB at first instance, since that decision has become devoid of purpose. 112. The present analysis has shown that the General Court was wrong to annul the decision at issue, even though the Commission had the power to adopt it, so that the forms of order sought by the Commission in that regard at first instance should have been upheld. Furthermore, point 2 of the operative part of the judgment under appeal, which rejects HB’s claim for compensation for material damage, must not be set aside. 113. However, the present analysis has also shown that the remedies against a set-off decision relating to a contractual claim falling within the jurisdiction of a national court are complex. Moreover, HB had taken all due care in bringing the matter before both the General Court and the competent national court to examine the merits of the claim in question in relation to the set-off at issue. 114. In those circumstances, it is fair to order each of the parties to bear its own costs relating to the proceedings at first instance, as the judgment under appeal did. The Commission’s request that point 3 of the operative part of that judgment be set aside and that HB be ordered to pay the costs of the proceedings before the General Court must therefore be rejected. VII. Conclusion 115. On the basis of the above considerations, I propose that the Court of Justice should: (1) Set aside point 1 of the operative part of the judgment of the General Court of the European Union of 4 October 2023, HB v Commission (T‑444/22, EU:T:2023:604); (2) Rule that there is no longer any need to adjudicate on the action for annulment in Case T‑444/22; (3) Order HB to bear its own costs and to pay those of the European Commission relating to the appeal proceedings. 1 Original language: French. 2 Judgments of 11 July 1985, Maag v Commission (43/84, EU:C:1985:328, paragraph 26); of 9 September 2015, Lito Maieftiko Gynaikologiko kai Cheirourgiko Kentro v Commission (C‑506/13 P, EU:C:2015:562, paragraph 19); and of 28 February 2019, Alfamicro v Commission (C‑14/18 P, EU:C:2019:159, paragraph 49). 3 See, to cite only the most emblematic of many cases in that field, judgments of 18 April 2013, Commission v Systran and Systran Luxembourg (C‑103/11 P, EU:C:2013:245); of 9 September 2015, Lito Maieftiko Gynaikologiko kai Cheirourgiko Kentro v Commission (C‑506/13 P, EU:C:2015:562); of 16 July 2020, ADR Center v Commission (C‑584/17 P, EU:C:2020:576); and of 26 September 2024, Commission v HB (C‑160/22 P and C‑161/22 P, EU:C:2024:799). See also, in that regard, my Opinions in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, point 95 et seq.), and in Commission v HB (C‑160/22 P, C‑161/22 P and C‑597/22 P, EU:C:2024:84, point 60 et seq.). 4 Judgment of 16 July 2020 (C‑584/17 P, EU:C:2020:576, paragraph 73). 5 In that connection, see also my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, points 48 to 58 and 95 to 105). 6 Judgment of 4 October 2023, HB v Commission (T‑444/22, ‘the judgment under appeal’, EU:T:2023:604). 7 Judgment under appeal, paragraphs 56, 57, 60 and 61. 8 Regulation of the European Parliament and of the Council of 18 July 2018 on the financial rules applicable to the general budget of the Union, amending Regulations (EU) No 1296/2013, (EU) No 1301/2013, (EU) No 1303/2013, (EU) No 1304/2013, (EU) No 1309/2013, (EU) No 1316/2013, (EU) No 223/2014, (EU) No 283/2014 and Decision No 541/2014/EU and repealing Regulation (EU, Euratom) No 966/2012 (OJ 2018 L 193, p. 1). That regulation has now been replaced by Regulation (EU, Euratom) 2024/2509 of the European Parliament and of the Council of 23 September 2024 on the financial rules applicable to the general budget of the Union (OJ L, 2024/2509). 9 Judgment of 21 December 2021, HB v Commission (T‑795/19, EU:T:2021:917, paragraph 4). 10 T‑795/19, EU:T:2021:917. 11 T‑796/19, EU:T:2021:918. 12 EU:C:2024:799. 13 See Opinion of Advocate General Léger in Commission v CCRE (C‑87/01 P, EU:C:2002:501, point 26), and Opinion of Advocate General Spielmann in E. (Set-off of claims) (C‑481/24, EU:C:2025:632, point 22 et seq.). 14 Judgment of 19 September 2024, Coppo Gavazzi and Others v Parliament (C‑725/20 P, EU:C:2024:766, paragraph 40 and the case-law cited). 15 Judgments of 8 July 1999, Commission v Anic Partecipazioni (C‑49/92 P, EU:C:1999:356, paragraph 171); of 22 February 2005, Commission v max.mobil (C‑141/02 P, EU:C:2005:98, paragraph 48); and of 21 December 2016, Council v Front Polisario (C‑104/16 P, EU:C:2016:973, paragraphs 69 and 70). Nor do those privileged applicants have to demonstrate an interest in bringing proceedings in order to bring an action for annulment; see judgment of 13 October 2011, Deutsche Post and Germany v Commission (C‑463/10 P and C‑475/10 P, EU:C:2011:656, paragraph 36). 16 See my Opinion in Council v Zhejiang Xinan Chemical Industrial Group (C‑337/09 P, EU:C:2012:22, point 35). 17 Opinion of Advocate General Mengozzi in Commission v Siemens Österreich and Others and Siemens Transmission & Distribution and Others v Commission (C‑231/11 P to C‑233/11 P, EU:C:2013:578, point 33). 18 See, to that effect, Opinion of Advocate General Poiares Maduro in Commission v max.mobil (C‑141/02 P, EU:C:2004:646, point 19). 19 Opinion of Advocate General Poiares Maduro in Commission v max.mobil (C‑141/02 P, EU:C:2004:646, point 21). 20 See, to that effect, judgment of 19 July 2012, Council v Zhejiang Xinan Chemical Industrial Group (C‑337/09 P, EU:C:2012:471, paragraph 50). 21 See, inter alia, judgments of 6 March 1979, Simmenthal v Commission (92/78, EU:C:1979:53, paragraph 32); of 7 June 2007, Wunenburger v Commission (C‑362/05 P, EU:C:2007:322, paragraphs 55 to 62); of 28 May 2013, Abdulrahim v Council and Commission (C‑239/12 P, EU:C:2013:331, paragraph 63); of 4 September 2018, ClientEarth v Commission (C‑57/16 P, EU:C:2018:660, paragraph 48); and of 19 September 2024, Coppo Gavazzi and Others v Parliament (C‑725/20 P, EU:C:2024:766, paragraph 42). 22 See, inter alia, judgments of 19 September 2024, Coppo Gavazzi and Others v Parliament (C‑725/20 P, EU:C:2024:766, paragraphs 43 to 47); Santini and Others v Parliament (C‑198/21 P, EU:C:2024:768, paragraphs 38 to 42); and of 19 September 2024, Falqui v Parliament (C‑391/21 P, EU:C:2024:769, paragraphs 41 to 44). 23 Judgments of 26 April 1988, Asteris and Others v Commission (97/86, 99/86, 193/86 and 215/86, EU:C:1988:199, paragraph 27); of 3 October 2000, Industrie des poudres sphériques v Council (C‑458/98 P, EU:C:2000:531, paragraph 81); and of 20 June 2024, EUIPO v Indo European Foods (C‑801/21 P, EU:C:2024:528, paragraph 92). 24 See, to that effect, judgments of 21 December 2011, France v People’s Mojahedin Organization of Iran (C‑27/09 P, EU:C:2011:853, paragraph 49), and of 19 July 2012, Council v Zhejiang Xinan Chemical Industrial Group (C‑337/09 P, EU:C:2012:471, paragraph 47). 25 See, for the importance of the grounds of the judgment under appeal in assessing the subject matter of the appeal, Opinion of Advocate General Poiares Maduro in Commission v max.mobil (C‑141/02 P, EU:C:2004:646, point 22), and Opinion of Advocate General Mengozzi in Commission v Siemens Österreich and Others and Siemens Transmission & Distribution and Others v Commission (C‑231/11 P to C‑233/11 P, EU:C:2013:578, points 34 to 38). 26 Judgments of 14 September 1999, Commission v AssiDomän Kraft Products and Others (C‑310/97 P, EU:C:1999:407, paragraph 54); of 1 June 2006, P & O European Ferries (Vizcaya) and Diputación Foral de Vizcaya v Commission (C‑442/03 P and C‑471/03 P, EU:C:2006:356, paragraph 44); and of 19 April 2012, Artegodan v Commission (C‑221/10 P, EU:C:2012:216, paragraph 87). 27 See, for the consideration of that aspect when assessing whether the appeal still has a purpose, order of 1 December 2004, OHIM v Zapf Creation (C‑498/01 P, EU:C:2004:760, paragraph 12), and judgments of 21 December 2011, France v People’s Mojahedin Organization of Iran (C‑27/09 P, EU:C:2011:853, paragraph 48), and of 19 July 2012, Council v Zhejiang Xinan Chemical Industrial Group (C‑337/09 P, EU:C:2012:471, paragraph 51). 28 Emphasis added. 29 See, for the definition of a claim regarded as uncontested, Article 3 of Regulation (EC) No 805/2004 of the European Parliament and of the Council of 21 April 2004 creating a European Enforcement Order for uncontested claims (OJ 2004 L 143, p. 15). 30 See, to that effect, Article 317 and Article 322(1) TFEU, and the judgment in ADR, paragraph 100 and the case-law cited. See also, to that effect, even before the codification of set-off as a means of recovering amounts receivable by the European Union by Article 73 of Council Regulation (EC, Euratom) No 1605/2002 of 25 June 2002 on the Financial Regulation applicable to the general budget of the European Communities (OJ 2002 L 248, p. 1), Opinion of Advocate General Léger in Commission v CCRE (C‑87/01 P, EU:C:2002:501, point 68). 31 See judgments of 17 January 2007, Greece v Commission (T‑231/04, EU:T:2007:9, paragraph 118), and of 21 September 2017, Eurofast v Commission (T‑87/16, EU:T:2017:641, paragraph 65). See also, to that effect, judgment of 8 November 2011, Walton v Commission (T‑37/08, EU:T:2011:640, paragraph 60). 32 Judgment of 9 September 2015, Lito Maieftiko Gynaikologiko kai Cheirourgiko Kentro v Commission (C‑506/13 P, EU:C:2015:562, paragraph 20), and the judgment in ADR, paragraph 65. 33 See Opinion of Advocate General Léger in Danværn Production (C‑341/93, EU:C:1995:139, points 27 to 31), and Commission v CCRE (C‑87/01 P, EU:C:2002:501, points 44 and 45), and Opinion of Advocate General Spielmann in E. (Set-off of claims) (C‑481/24, EU:C:2025:632, point 22 et seq.). 34 The present case concerned the costs which the Commission had been ordered to pay in another case; see, for other examples, the case which gave rise to the judgment of 10 July 2003, Commission v CCRE (C‑87/01 P, EU:C:2003:400) (subsidy granted, moreover, to the Commission’s co-contractor), or the case which gave rise to the judgment of 11 July 2019, IPPT PAN v Commission and REA (T‑805/16, EU:T:2019:496) (debt owed to the Commission’s co-contractor under another contract). 35 ADR judgment, paragraphs 69 and 70. See also my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, points 100 to 104). See also, to that effect, judgments of 17 January 2019, Aristoteleio Panepistimio Thessalonikis v ERCEA (T‑348/16 OP, EU:T:2019:14, paragraph 165), and of 11 July 2019, IPPT PAN v Commission and REA (T‑805/16, EU:T:2019:496, paragraph 175). 36 See, inter alia, judgments of 8 October 2008, Helkon Media v Commission (T‑122/06, EU:T:2008:418, paragraphs 46 to 52); of 6 October 2015, Technion and Technion Research & Development Foundation v Commission (T‑216/12, EU:T:2015:746, paragraph 53); and of 14 November 2017, Alfamicro v Commission (T‑831/14, EU:T:2017:804, paragraphs 191 to 193). The General Court based that line of case-law, inter alia, on the judgment of 10 July 2003, Commission v CCRE (C‑87/01 P, EU:C:2003:400, paragraphs 42 and 45, and the operative part). 37 ADR judgment, paragraph 73. 38 See the combined provisions of Article 161(1) and Article 156(1) and (2) of the Rules of Procedure of the General Court, and the combined provisions of Article 165(1) and Article 160(1) and (2) of the Rules of Procedure of the Court of Justice, as well as my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, point 49). 39 ADR judgment, paragraph 88. See, also, my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, points 133 to 136). 40 See my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, footnote 41). 41 See, for a similar solution, Paragraph 322(1) of the Zivilprozessordnung (German Code of Civil Procedure), according to which judgments can acquire the force of res judicata only in so far as they rule on applications lodged. 42 Similar questions arise in general where the examination of the merits of the claim recovered by way of set-off (potentially) falls within the jurisdiction of a court other than the General Court; see, in that regard, judgments of 5 February 2025, Poland v Commission (T‑830/22 and T‑156/23, EU:T:2025:131, paragraphs 23 to 31) (appeal pending in Case C‑296/25 P), and Poland v Commission (T‑1033/23, EU:T:2025:129, paragraphs 18 to 26) (appeal pending in Case C‑297/25 P). The same does not apply where the General Court has jurisdiction to rule on the merits of the counterclaim recovered: see, for example, judgment of 11 July 2019, IPPT PAN v Commission and REA (T‑805/16, EU:T:2019:496, paragraph 33 et seq.); see, however, in that regard, the judgment in ADR, paragraphs 80 to 89, and my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, point 113 et seq.). 43 See, to that effect, judgment of 17 January 2019, Aristoteleio Panepistimio Thessalonikis v ERCEA (T‑348/16 OP, EU:T:2019:14, paragraphs 175 and 176). Similarly, it seems conceivable that the other party to the contract may, where appropriate, challenge before the court having jurisdiction the amount of the principal claim for which the Commission acknowledges that it is liable, if it does not agree with that amount. Nor can the set-off decision, if confirmed by the General Court, confer definitive legal force on the determination of that amount if its examination falls within the jurisdiction of a court other than the General Court. 44 See, to that effect, mutatis mutandis, judgment of 4 May 2017, Meta Group v Commission (T‑744/14, EU:T:2017:304, paragraphs 47, 49 and 258). 45 See, on the present point, my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, point 111). 46 See my Opinion in ADR Center v Commission (C‑584/17 P, EU:C:2019:941, footnote 41). See also, to that effect, Opinion of Advocate General Léger in Commission v CCRE (C‑87/01 P, EU:C:2002:501, point 57). 47 See the third subparagraph of Article 101(1), the first subparagraph of Article 102(1) and Article 103 of the 2018 Financial Regulation. 48 See judgments of 15 April 2011, Czech Republic v Commission (T‑465/08, EU:T:2011:186, paragraphs 129 and 130), and of 21 September 2017, Eurofast v Commission (T‑87/16, EU:T:2017:641, paragraphs 67 and 68). 49 See Article 103 of the 2018 Financial Regulation.