Provisional text
OPINION OF ADVOCATE GENERAL
ĆAPETA
delivered on 30 October 2025 (1)
Case C‑293/24
João Filipe Ferreira da Silva e Brito and Others
v
Estado português
(Request for a preliminary ruling from the Supremo Tribunal de Justiça (Supreme Court, Portugal))
( Reference for a preliminary ruling – Liability of a Member State for damage caused to individuals as a result of breaches of EU law attributable to a national court of last instance – Sufficiently serious breach of EU law – Assessment – Transfers of undertakings – Safeguarding of employees’ rights – Directives 77/187/EEC and 2001/23/EC – Article 1(1) – Concept of a ‘transfer of a business’ – Third paragraph of Article 267 TFEU – Obligation to make a reference for a preliminary ruling )
I.      Introduction
1.        In Köbler, (2) the Court made it clear that a Member State may be held liable for damages due to judicial errors of its national courts of last instance. Such liability exists only if those errors represent a sufficiently serious breach of EU law. A question, not yet fully clarified, is how does the failure of such courts to refer to the Court under the third paragraph of Article 267 TFEU contribute to the seriousness of the breach.
2.        That question was raised by the present request for a preliminary ruling submitted by the Supremo Tribunal de Justiça (Supreme Court, Portugal) in the context of domestic litigation that started over three decades ago.
3.        The present case therefore provides the Court with the opportunity to clarify how the Köbler and CILFIT (3) case-law interact and to build upon its judgment in Consorzio. (4)
II.    Background to the present case, the questions referred and the procedure before the Court
4.        The background to the present case dates back to 1993, when Air Atlantis, SA (‘AIA’), a Portuguese airline company operating in the non-scheduled air transport (charter flights) sector, was dissolved. That in turn led to two sets of proceedings before the Portuguese courts. As both are relevant for understanding the issues raised by the present case, I will briefly describe them below.
A.      First set of proceedings (relating to the claim that a transfer of a business occurred)
5.        In the process of dissolving AIA, that company’s employees were the subject of a collective redundancy measure. However, shortly thereafter, they became aware that some of AIA’s aircraft had moved to the Portuguese airline company TAP Air Portugal (‘TAP’), which was the majority shareholder of AIA. Likewise, TAP had begun to operate charter flights on routes previously served by AIA. Those employees therefore considered that AIA’s business had been transferred to TAP.
6.        Consequently, in 1993 and 1994, the former AIA employees brought actions challenging the collective redundancy before the Tribunal do Trabalho de Lisboa (Labour Court, Lisbon, Portugal; ‘the Lisbon Labour Court’). They sought, in particular, reinstatement within TAP and payment of remuneration on the grounds that there had been a transfer of a business.
7.        The decision on their claims depended, among other things, on the application of Directive 77/187/EEC, (5) relating to the safeguarding of employees’ rights in the event of transfers of undertakings, which was, during the course of the proceedings, replaced by Directive 2001/23/EC. (6)
8.        Under Directives 77/187 and 2001/23, employees enjoy certain rights in the event of a change of employer. In particular, their employment relationship is automatically transferred from the old to the new employer and they are protected against dismissal due solely to the transfer. (7)
9.        However, according to Article 1(1) of Directives 77/187 and 2001/23, in order to fall within their scope, there must be a ‘transfer of an undertaking, business, or part of an undertaking or business to another employer as a result of a legal transfer or merger’. That concept – which I will refer to as a ‘transfer of a business’ – is thus a crucial gateway to the rights granted to employees by those directives. Originally, there was no definition of the concept of a ‘transfer of a business’ in Directive 77/187, so its interpretation fell to the Court. That directive was later amended by Directive 98/50, so as to take account of the Court’s case-law. Directive 2001/23 codified Directive 77/187 without changing it. (8)
10.      After the introduction of the actions by the former AIA employees, it took the Lisbon Labour Court almost 15 years to decide on their claims. (9) By judgment of 6 February 2007, (10) that court held that there had been a transfer of a business and ordered TAP to reinstate the employees and pay them damages and lost earnings.
11.      Appeals were lodged against that judgment before the Tribunal da Relação de Lisboa (Court of Appeal, Lisbon, Portugal; ‘the Lisbon Court of Appeal’). By judgment of 16 January 2008, (11) that court set aside the lower-court judgment and dismissed the actions, finding that there had not been a transfer of a business from AIA to TAP.
12.      The employees lodged appeals against that judgment before the Supremo Tribunal de Justiça (Supreme Court, Portugal; ‘the Portuguese Supreme Court’). They relied, inter alia, on the Court of Justice’s case-law relating to Directives 77/187 and 2001/23, and requested that a preliminary reference be made to the Court of Justice.
13.      By judgment of 25 February 2009 (‘the 2009 judgment’), (12) the Portuguese Supreme Court dismissed those appeals. In particular, that court held that it was not possible on the basis of the facts of the case to find that there had been a transfer of a business from AIA to TAP. (13) That court also considered that it was not obliged to make a preliminary reference to the Court of Justice and rejected the employees’ requests to do so. (14)
B.      Second set of proceedings (relating to the claim for damages against the Portuguese State)
14.      Following dismissal of their case, Mr Ferreira da Silva e Brito and 96 other former employees of AIA brought an action for damages against the Portuguese State before the Varas Cíveis de Lisboa (Court of First Instance, Lisbon, Portugal; ‘the Lisbon Court of First Instance’). Those applicants based their action on alleged breaches of EU law by the Portuguese Supreme Court in the 2009 judgment.
15.      They contended that that judgment was manifestly unlawful because the Portuguese Supreme Court incorrectly interpreted the concept of a ‘transfer of a business’ within the meaning of Directive 2001/23 and because that court failed to comply with the obligation to make a preliminary reference regarding the interpretation of that concept.
16.      In the context of those proceedings, the Lisbon Court of First Instance requested a preliminary ruling from the Court of Justice. That request gave rise to the judgment of 9 September 2015, Ferreira da Silva e Brito and Others (‘Ferreira I’). (15)
17.      In that judgment, the Court ruled, in particular, that the concept of a ‘transfer of a business’ within the meaning of Article 1(1) of Directive 2001/23 ‘encompasses a situation in which an undertaking active on the charter flights market is wound up by its majority shareholder, which is itself an air transport undertaking, and the latter undertaking then takes the place of the undertaking that has been wound up by taking over aircraft leasing contracts and ongoing charter flight contracts, carries on activities previously carried on by the undertaking that has been wound up, reinstates some employees that have hitherto been seconded to that undertaking, assigning them tasks identical to those previously performed, and takes over small items of equipment from the undertaking that has been wound up’. (16)
18.      The Court considered that, in the air transport sector, the fact that tangible assets are transferred must be regarded as a key factor and that other factors gave a strong indication of a transfer. (17) The Court also relied on the judgment in Klarenberg (18) – which had been delivered several days before the 2009 judgment – to find that what matters is the retention of a functional link between the various elements transferred, even if they are integrated into a new and different organisational structure after the transfer. (19)
19.      Additionally, in Ferreira I, the Court held that, in circumstances such as the case at hand which are characterised both by conflicting decisions of lower courts and difficulties of interpretation in the various Member States, a national court of last instance is obliged under the third paragraph of Article 267 TFEU to make a preliminary reference concerning the interpretation of the concept of a ‘transfer of a business’. (20) The Court emphasised that, in the area concerned, the interpretation of that concept had given rise to uncertainty on the part of many national courts, which found it necessary to make preliminary references; that uncertainty ‘shows not only that there are difficulties of interpretation, but also that there is a risk of divergences in judicial decisions within the European Union’ and that therefore a last-instance court must comply with its obligation to refer ‘in order to avert the risk of an incorrect interpretation of EU law’. (21)
20.      Thereafter, by judgment of 20 January 2020, (22) the Tribunal Judicial da Comarca de Lisboa (District Court, Lisbon, Portugal; ‘the Lisbon District Court’), which apparently had meanwhile succeeded the Lisbon Court of First Instance, dismissed the action on the grounds that no sufficiently serious breach of EU law had been shown. (23)
21.      Some of those applicants brought an appeal against that judgment before the Lisbon Court of Appeal. By judgment of 16 March 2023, (24) that court dismissed the appeal. It considered that the Portuguese Supreme Court should have referred to the Court of Justice, but that that court did not incorrectly interpret the concept of a ‘transfer of a business’. It therefore found that no sufficiently serious breach of EU law existed. (25)
22.      Mr Ferreira da Silva e Brito and a number of other applicants (‘the applicants’) lodged an appeal against that judgment before the Portuguese Supreme Court, which is the referring court in the present case.
23.      That court notes that, in the Ferreira I judgment, the Court ruled on whether the factual situation of the present case could be covered by the concept of a ‘transfer of a business’ within the meaning of Directive 2001/23 without reference to the time when the 2009 judgment was given, that is, on 25 February 2009. That would make it necessary to take into account the case-law of the Court as it existed on that date. The referring court further points out that, in the Ferreira I judgment, the Court considered that the Portuguese Supreme Court had breached Article 267 TFEU by refusing, in the 2009 judgment, to request a preliminary ruling. However, the Court did not rule in that judgment on whether the breach was sufficiently serious, as it had not been asked to do so.
24.      By the present reference, the referring court therefore seeks to ascertain whether the response given in Ferreira I is also applicable to the time when the 2009 judgment, which allegedly breached EU law, was given.
25.      That court also asks whether there is a sufficiently serious breach of EU law in the 2009 judgment, either on account of having incorrectly interpreted the concept of a ‘transfer of a business’ in the light of EU law, or on account of having failed to comply with the obligation to make a preliminary reference. (26)
26.      Additionally, should the Court conclude that there has been a sufficiently serious breach of EU law, the referring court wonders whether, for the purposes of assessing the condition relating to a causal link, the applicable national legislation, (27) which provided that an employee’s taking of compensation constituted acceptance of the dismissal and thus precluded the employee from challenging the dismissal, runs counter to the provisions of Directive 77/187, the EU law in force at the time.
27.      Under those circumstances, the Portuguese Supreme Court decided to stay the proceedings and to refer the following questions to the Court of Justice for a preliminary ruling:
‘(1)      In view of the proven facts set out above and the case-law of the Court of Justice as it stood at 25 February 2009, should [Directive 77/187] and [Directive 2001/23], in particular Article 1(1) of [Directive 2001/23], which clarified the concept of “transfer”, have been interpreted on that date as meaning that the concept of [a] “transfer of a business” encompassed a situation in which an undertaking active in the charter flights market was wound up by a decision of its majority shareholder, which was itself an undertaking active in the aviation sector and which, in the context of the winding-up, carried out the acts which are described in greater detail in the proven facts set out above?
(2)      If the answer is in the affirmative and likewise in view of the proven facts set out above and the case-law of the Court of Justice as it stood at 25 February 2009, does the decision contained in the judgment given on that same date by the Supremo Tribunal de Justiça [(Supreme Court)], which, deciding at last instance and in the light of the facts of which it was aware, held that the abovementioned directives, in particular Article 1(1) of [Directive 2001/23], should be interpreted as meaning that the concept of [a] “transfer of a business” did not encompass the situation described in the previous question, constitute a sufficiently serious breach of EU law?
(3)      In view of the proven facts set out above and the case-law of the Court of Justice as it stood at 25 February 2009, does the decision contained in the judgment given on that same date by the Supremo Tribunal de Justiça (Supreme Court), which, deciding at last instance and in the light of the facts of which it was aware, held that Article 234 TEC (now Article 267 TFEU) should be interpreted as meaning that, in view of the facts described in the first question referred and the fact that the lower national courts that had heard the case had given conflicting decisions, the Supremo Tribunal de Justiça (Supreme Court) was not obliged to request a preliminary ruling from the Court of Justice regarding the correct interpretation of the concept of [a] “transfer of a business” for the purposes of Article 1(1) of [Directive 2001/23], constitute a sufficiently serious breach of EU law?
(4)      If the answer to the first question is in the affirmative and if the answer to either or both of the previous two questions is in the affirmative, the conclusion having been reached that there is a sufficiently serious breach of EU law – in a case such as the present one, in which it has been proved that the employees agreed to receive compensation for the collective redundancy, as they were convinced that the dissolution of Air Atlantis, their employer, was inevitable and were unaware that, after the termination of their contracts of employment, TAP would carry on at least part of the charter flight activity which, until then, had been carried on by Air Atlantis and that some of Air Atlantis’s equipment, including the aircraft, would be transferred to TAP – must Article 3(1) of [Directive 77/187] be interpreted as meaning that it precludes a national provision, such as Article 23(3) of Decree-Law No 64-A/89 of 27 February [1989], which has since been repealed but was applicable at the time of the facts in the main proceedings, in accordance with which “where the employee takes the compensation referred to in this article, it equates to acceptance of the dismissal”?’
28.      Written observations were submitted to the Court by the applicants, the Portuguese Government and the European Commission.
29.      A hearing was held on 16 June 2025 at which all of those interested parties, along with the German and Spanish Governments, presented oral argument.
III. Analysis
30.      Four questions have been referred in the present case. In essence, the referring court asks the following. First, is the finding in the 2009 judgment that there was no transfer of a business a breach of the applicable EU law? Second, if that finding was wrong, is that a sufficiently serious breach, capable of establishing State liability for damages? Third, is the Portuguese Supreme Court’s finding that it was not obliged to make a preliminary reference a sufficiently serious breach? Fourth, do the provisions of Directive 77/187 preclude national legislation which deprived employees of their right to challenge their collective redundancy upon acceptance of the compensation to which they were entitled?
31.      As requested by the Court, I will focus my analysis on the third question.
32.      As the question whether a breach of EU law is sufficiently serious presupposes that there was a breach in the first place, I will proceed on the assumption that, in the answer to the first question, the Court would find such a breach.
33.      I will explain below why a breach of the obligation to refer cannot engage State liability for damages in itself. In that light, asking separately whether a breach of the obligation to refer is sufficiently serious is ill fitting. I, therefore, understand the third question as asking how a breach of the obligation to refer contributes to the finding that a breach of EU law, which is intended to confer rights on individuals, is sufficiently serious.
34.      My analysis starts with the concept of a sufficiently serious breach and the Köbler case-law. It ends with the conclusion that a breach of the obligation to refer, enumerated in that case-law as one of the relevant factors for finding a breach of EU law to be sufficiently serious, may contribute to such a finding in situations where a court of last instance unintentionally committed a judicial error. In that respect, a sufficiently serious breach is the result of an incorrect interpretation or application of EU law, which is intended to confer rights on individuals, coupled with a breach of the obligation to refer (A).
35.      To contribute to the seriousness of the breach, the obligation to refer must exist in the particular case. To establish when the obligation to refer exists, I will analyse the CILFIT case-law, as recently developed in Consorzio. I will examine the issue left open in Consorzio as to whether a court of last instance is under an obligation to refer only if there exists a reasonable doubt about the correct interpretation of EU law, as opposed to its correct application which seems to be the situation in the present case. I consider that a distinction between interpretation and application cannot be usefully made in order to exclude certain judicial decisions from the obligation to refer. That means that a breach of the obligation to refer regarding the application of EU law can also contribute to the finding of a sufficiently serious breach (B).
36.      Nevertheless, as I will discuss under (C), a breach of the obligation to refer may be excused if a court of last instance has provided acceptable reasons for not referring, including an explanation as to why it considered its application of EU law, including pertinent case-law of the Court, to be correct in the circumstances of the case.
37.      Finally, under (D), I will apply my analysis to the present case as regards whether the Portuguese Supreme Court may be excused for deciding not to make a preliminary reference in the 2009 judgment.
A.      A sufficiently serious breach of EU law
1.      The Köbler standard (28)
38.      In Köbler, (29) the Court extended the principle of State liability for damage caused to individuals due to breaches of EU law (which I will refer to as ‘State liability’), previously developed and applied in relation to national executive and legislative authorities, (30) to situations in which the breach of EU law is attributable to national courts of last instance.
39.      As the Court held, the conditions for such liability remain the same: the rule of EU law infringed must be intended to confer rights on individuals; the breach must be sufficiently serious; and there must be a direct causal link between the breach of the obligation incumbent on the Member State and the loss or damage sustained by the injured parties. (31)
40.      Thus, State liability, whatever the institution of a Member State to which the breach is attributable, does not arise for every breach of EU law, but only for those breaches that may be characterised as sufficiently serious. That means that the harm inflicted on an individual is not redressed every time his or her EU-based rights have been breached. Rather, the concept of State liability, as developed in EU law, strikes a balance between the need to ensure the effective protection of individual rights, on the one hand, and the need to enable the unfettered functioning of State institutions in performing their public tasks, on the other. (32)
41.      Applying such balancing to State liability attributable to courts of last instance in Köbler, the Court considered that the specific nature of the judicial function must be taken into consideration when establishing criteria for a sufficiently serious breach. The Court therefore found that liability for judicial errors ‘can be incurred only in the exceptional case where the court has manifestly infringed the applicable law’. (33) The Köbler standard is thus a manifest breach of EU law.
42.      It is, therefore, possible to conclude that if an error in the interpretation or application of EU law is committed bona fide in the exercise of the court’s function, State liability does not arise.
2.      Factors for assessing the seriousness of the breach
43.      There is, however, no ‘one size fits all’ formula to determine whether a breach is manifest. Rather, the Court has set out several factors that could be relevant in that determination. (34) The majority of those factors – the degree of clarity and precision of the rule infringed, whether the infringement was intentional, whether the error of law was excusable or inexcusable, or the position taken by an EU institution – had already been mentioned in case-law that did not relate to breaches attributable to last-instance courts, but to other national authorities. (35) To that list, the Court added non-compliance with the obligation to make a reference for a preliminary ruling under the third paragraph of Article 267 TFEU.
44.      The breach of the obligation to refer is thus one of the factors that can influence the characterisation of an incorrect interpretation of EU law by a national court as sufficiently serious. Unlike the other enumerated factors, it is relevant only for State liability attributable to courts of last instance.
45.      The breach of the obligation to refer, which only courts of last instance may commit, can affect how other factors are weighed in the assessment whether a breach is sufficiently serious. For example, the degree of clarity of the rule breached is to be assessed differently when the breach is committed by an administrative or legislative authority, as compared to a situation where the insufficient clarity of a rule leads to an erroneous understanding and application of the rule by a national court of last instance. If the rule is unclear, a national court of last instance must make a preliminary reference to the Court of Justice. On the contrary, a different State body, for example, a ministry, cannot ask for clarification from the Court of Justice. The insufficient clarity of a rule may thus excuse a breach of that rule by a national administrative authority, (36) but cannot excuse a national court of last instance which did not make a preliminary reference.
46.      It seems to me that the main question to be answered when assessing whether a breach is sufficiently serious essentially boils down to whether the error committed by a State body, including a court of last instance, is excusable or inexcusable. (37)
47.      A breach would obviously be inexcusable if a court of last instance intentionally applied an EU rule contrary to its clear meaning. That includes manifest breaches of case-law of the Court. (38) I would add to this, situations in which a court of last instance disregards the existence of EU law, including case-law of the Court, and decides the case by applying only national law, especially in situations where the parties to the proceedings relied on EU law before that court. Such situations could be understood as intentional avoidance of EU law and therefore also a manifest breach.
3.      Contribution of a breach of the obligation to refer to the finding of a sufficiently serious breach
48.      When, however, the breach, consisting in an incorrect interpretation of EU law as applied in the case, is not intentional, the Köbler case-law seems to suggest that it may nevertheless be considered sufficiently serious if the court of last instance did not make a reference for a preliminary ruling in breach of its obligation under the third paragraph of Article 267 TFEU.
49.      Thus, depending on the circumstances, a court of last instance might, in principle, be excused for a misunderstanding of EU law resulting in an incorrect decision, but it cannot be excused for such an error if it did not ask for the Court’s interpretation through the preliminary ruling procedure even though it was under such an obligation.
50.       The third question of the referring court is framed as asking whether the breach of the Portuguese Supreme Court of its obligation to refer is sufficiently serious. That prompted discussion among the participants to these proceedings whether a breach of the obligation to refer can on its own establish State liability.
51.      In my view, a breach of the obligation to refer cannot on its own result in State liability.
52.      An action based on State liability serves to remedy the harmful consequences of the breach of an individual’s rights based on EU law. If that breach is the result of a judicial error by a national court of last instance, the provision of EU law breached must be intended to confer rights on individuals.
53.      The obligation to refer is not owed by a national court of last instance to a party. In other words, as claimed in these proceedings by the applicants as well as the German and Spanish Governments, the third paragraph of Article 267 TFEU is not a rule intended to confer rights on individuals. (39) As there is no right, there can be no breach of that right and hence no State liability for that breach. In short, an action for damages based on State liability is not a method of enforcement of the obligation to refer. (40)
54.      In the context of that action, the breach of the obligation to refer becomes relevant only as a factor contributing to the finding that an incorrect interpretation or application of EU law intended to confer rights on individuals is sufficiently serious to engage State liability. (41) If a court of last instance did not refer, even though it was under an obligation to do so, but it nevertheless interpreted and applied EU law correctly, no reparable damage arises and no State liability is incurred.
55.      If, however, a court of last instance incorrectly interpreted or applied EU law, thus depriving an individual of his or her EU-based rights, such a breach is to be considered sufficiently serious if the court incorrectly failed to refer. That is so because the breach of individual rights would not have occurred had the court abided by its obligation to refer, thus enabling the Court of Justice to provide the correct interpretation of EU law.
56.      Accordingly, the formula for assessing whether an unintentional breach of EU law by a court of last instance is sufficiently serious seems to be: breach of EU law conferring rights on individuals + breach of the obligation to refer = sufficiently serious breach.
57.      That formula raises two issues relevant for answering the third question, which I will address in turn. First, does a court of last instance have an obligation to refer if it is uncertain about the correct application, rather than the correct interpretation, of EU law? If doubts about application do not trigger the obligation to refer, the non-referral cannot be a factor that leads to a sufficiently serious breach. Second, if a court of last instance does breach its obligation to refer, one may ask whether that breach may nevertheless be excused, so that there is no sufficiently serious breach.
58.      In the latter scenario, the formula would have to be slightly modified: breach of EU law conferring rights on individuals + inexcusable breach of the obligation to refer = sufficiently serious breach.
59.      To sum up, for the purpose of establishing whether a judicial error by a court of last instance represents a sufficiently serious breach to engage State liability, a breach of the obligation to refer is only a factor to be taken into consideration. A breach of the obligation to refer cannot in itself result in State liability. If the court erroneously fails to refer, but applies EU law correctly, no such liability can be incurred. If the court intentionally misapplies EU law, the breach is sufficiently serious in itself. However, in a situation of an unintentional breach of EU law intended to confer rights on individuals, that breach is sufficiently serious if the court breached its obligation to refer under the third paragraph of Article 267 TFEU.
B.      When is there an obligation to refer
1.      CILFIT
60.      The third paragraph of Article 267 TFEU imposes an obligation on national courts of last instance to refer to the Court questions of interpretation (or validity) of EU law, which they need in order to decide the case pending before them.
61.      In CILFIT, the Court identified three situations – irrelevance, ‘acte éclairé’ and ‘acte clair’ – in which national courts of last instance do not have such an obligation to refer. (42)
62.      Leaving aside the first situation, which is not pertinent in the present case, the ‘acte éclairé situation applies where the Court has already interpreted the applicable rule of EU law in an identical situation or in a similar situation even though the questions at issue were not strictly identical. (43) The ‘acte clair’ situation applies where the correct application of EU law is so obvious ‘as to leave no scope for any reasonable doubt as to the manner in which the question raised is to be resolved’. (44)
63.      When applied to the present case, it is not entirely clear to me whether the Portuguese Supreme Court’s decision not to refer could be understood as potentially justified under ‘acte éclairé’ or ‘acte clair’. At the time when the Portuguese Supreme Court delivered the 2009 judgment, a number of rulings in which the Court of Justice interpreted the concept of a ‘transfer of a business’ in Directives 77/187 and 2001/23 already existed. However, the situations in which those interpretations were provided were not identical to the circumstances of the present case.
64.      If the situations in which the Court of Justice already interpreted the concept of a ‘transfer of a business’ were sufficiently similar, the question whether there is a breach of the obligation to refer may be assessed in the light of the ‘acte éclairé’ situation. If not, it might be considered that the existing case-law contributed to the clarity of that concept so that when the Portuguese Supreme Court gave its ruling in 2009, it was already beyond a reasonable doubt as to how that concept was to be applied in the novel circumstances of the case at issue. The question whether there is a breach of the obligation to refer would then be assessed in the light of the ‘acte clair’ situation. (45)
65.      In my view, it is not necessary to classify the present case under one of those two situations. As the obligation to refer has as its primary purpose to ensure the uniformity of EU law, the question to be answered in order to decide whether there is a breach of the obligation to refer is the same: could the Portuguese Supreme Court conclude that it was beyond any reasonable doubt that the Court of Justice or the last-instance courts of other Member States would come to the same interpretation of the concept of a ‘transfer of a business’ as applied to the particular circumstances of the dispute pending before that court.
66.      If the answer to that question is in the affirmative, there was no breach of the obligation to refer and, consequently, the breach of EU law, unless intentional, cannot be considered sufficiently serious.
2.      Consorzio: interpretation versus application
67.      The CILFIT case-law was refined in Consorzio. In that case, the Court confirmed the three CILFIT situations, with two potentially important differences.
68.      First, in Consorzio, the Court, as noted by scholars, modified the wording according to which a preliminary reference is not necessary if the correct interpretation of EU law (rather than the correct application of EU law) is so obvious that it leaves no room for any reasonable doubt. (46) A question left unanswered is whether the Court wanted to exclude the obligation to refer in situations when a court of last instance has doubts about the correct application of EU law.
69.      Second, the Court considered that a last-instance court which decides not to refer must provide a statement of reasons for that decision in the light of the three CILFIT situations. (47) Such adequate reasoning, may, in my view, excuse a breach of the obligation to refer, resulting in the conclusion that no sufficiently serious breach was committed.
70.      The change of wording from application to interpretation in Consorzio prompted a lively scholarly discussion as to whether the Court had accepted Advocate General Bobek’s proposal in that case, which relied on the distinction between the interpretation and the application of EU law. (48) His proposal was that courts of last instance should be obliged to refer only when that was necessary for the uniform interpretation of EU law, and not when they had doubts about the correct application of EU law. (49)
71.      Advocate General Bobek explained that the purpose of the preliminary ruling procedure in assisting national courts with the application of EU law is served by the power of courts to refer; that is the reason why any national court always may refer. However, the preliminary ruling procedure also has a general objective in ensuring the uniform interpretation of EU law; that is the reason why last-instance courts must refer. For Advocate General Bobek, the obligation imposed under the third paragraph of Article 267 TFEU serves that latter purpose, and should not require last-instance courts to refer whenever the application of EU law might pose problems. In other words, if the court of last instance applies EU law, which was already interpreted or clear in itself, there is no obligation to refer.
72.      Scholars disagree about the significance of the change of wording in Consorzio. While some consider that it indicates that the Court accepted Advocate General Bobek’s proposal to distinguish between interpretation and application, (50) others are more cautious, explaining that the expression ‘the correct interpretation of EU law’ also encompasses the correct application of EU law. (51)
73.      Why is that question relevant in the context of the present case?
74.      In principle, national courts will need the interpretation of EU law from the Court of Justice in order to apply EU law to resolve a dispute pending before them. The question of interpretation of EU law is always related to the facts of the case at issue. Advocate General Bobek considered that possible differences as to how different national courts apply EU law should not raise concerns relating to the objective to ensure the uniform interpretation of EU law. Therefore, in his view, a court that needs help from the Court of Justice in order to apply EU law does not have an obligation to refer. It would then follow that if there is no obligation to refer, there cannot be a breach of that obligation which could be taken into consideration when assessing whether a breach of EU law conferring rights on individuals is sufficiently serious to incur State liability.
75.      If that proposal is accepted, a court ruling on an action for State liability would have to determine whether the court of last instance erred in the interpretation or the application of EU law. In the latter situation, it can exclude the breach of the obligation to refer as a factor that could lead to the conclusion that a breach of EU law conferring rights on individuals is sufficiently serious.
76.      If, however, the Court’s change of wording in Consorzio did not exclude questions of the application of EU law from the obligation to refer, there is no need to establish whether the court of last instance was interpreting or applying EU law.
77.      The error of the Portuguese Supreme Court in the 2009 judgment could be understood as an error in the application of EU law, as that court took into consideration the concept of a ‘transfer of a business’ in EU legislation as interpreted in pertinent case-law of the Court of Justice, but then incorrectly applied it to the situation at issue. (52) If the application of EU law does not trigger the obligation to refer, the breach of that obligation as a factor to assess the seriousness of the breach does not come into play. (53)
78.      That, however, was not the Court’s finding in Ferreira I.
Rather, the Court considered that the Portuguese Supreme Court should have referred. (54) That leads me to the conclusion that either the Court does not make a distinction between interpretation and application in relation to the obligation to refer, or it considered that the error committed by the Portuguese Supreme Court was an error of interpretation, not of application.
79.      Therefore, the Court’s clarification of the change of wording in Consorzio would make a difference in the answer to be provided to the referring court.
80.      That being said, I am not convinced that a distinction between interpretation and application should be used by the Court as a criterion for confirming or excluding the existence of the obligation to refer. That is so for two main reasons.
81.      The first reason is that a delineation between the two cannot be made on the basis of an objective rule. Interpretation could be described as a process leading to the understanding of the meaning of a rule. Application can be understood as a syllogism in which the premissa maior is a general legal rule, and the premissa minor are the facts of the case. The problem, however, is that, as stated by Advocate General Capotorti in CILFIT, application without interpretation is not possible; to apply the rule to the facts of the case, a court first must interpret it, if only to find that its meaning is perfectly clear. (55) Therefore, to decide that the premissa maior is clear, in the sense of the ‘acte clair’ situation, the court must first interpret that premiss.
82.      Consequently, the line between interpretation and application, based on some pre-set level of generality, cannot be established. Different persons may assess differently where interpretation stops and application begins. (56)
83.      The second reason why I consider that the Court should not make a distinction between interpretation and application is that differences in application may also be relevant from the perspective of the uniformity of EU law.
84.      Take Advocate General Bobek’s example of an application of EU law in relation to which a national court of last instance should not be obliged to refer: whether the collision of a plane with a bird represents an extraordinary circumstance which, on the basis of the applicable EU law, (57) relieves an airline company from the obligation to pay compensation to a passenger whose flight was cancelled or delayed. (58) He pointed out that the Court had already provided the interpretation of the notion ‘extraordinary circumstances’ as ‘an event which … is not inherent in the normal exercise of the activity of the air carrier concerned and is beyond the actual control of that carrier’. (59) In his view, when deciding whether the collision of a plane with a bird is an extraordinary circumstance, a court applies EU law.
85.      Nonetheless, even if I could agree that that is an example of application (if the distinction between interpretation and application is accepted), this situation might, for the sake of ensuring the uniformity of EU law, require a preliminary reference. It is possible that one court considers that a collision of a plane with a bird is inherent in the normal exercise of the activity of an air carrier (after all, planes fly), even if it is outside of its control and thus not an extraordinary circumstance. Another court could decide differently, finding that a collision of that kind is an extraordinary circumstance, as it does not happen often and the air carrier, in any case, cannot predict it. The consequence would be that the first court, which was wrong as we know today, (60) would order the airline to pay compensation, whereas the second court would not. Therefore, passengers and airlines that find themselves in the same situation would be treated differently.
86.      The general objective of ensuring the uniformity of EU law is not an end in itself; uniformity is necessary in order to enable equal treatment of subjects of EU law in equal situations. That means that, assessed in the light of the objective to ensure the uniformity of EU law, the courts in the example might be obliged to refer, even though they were merely applying EU law.
87.      To sum up, in my view, the Court should not rely on the distinction between interpretation and application in order to exclude application from the obligation to refer under the third paragraph of Article 267 TFEU. (61) Accordingly, if a court of last instance incorrectly applied EU law intended to confer rights on individuals, the failure to refer might lead to a sufficiently serious breach for the purposes of State liability. In other words, incorrect application can constitute the second element in the equation as stated in point 56 of this Opinion.
88.      In the present case, even if one could consider that the Portuguese Supreme Court was applying, rather than interpreting, the EU concept of a ‘transfer of a business’, it should not, simply on that basis, be relieved from the obligation to refer. Its decision not to refer may only be justified if that court considered that the Court of Justice and other last-instance courts would apply that concept in the same way in the circumstances of the case.
89.      In Ferreira I, as explained, the Court considered that the Portuguese Supreme Court was obliged to refer in the circumstances of the case at issue. That seems to suggest that it did breach its obligation to refer under the third paragraph of Article 267 TFEU, which would lead to the conclusion that its incorrect application of the EU concept of a ‘transfer of a business’ was sufficiently serious.
90.      However, it is still possible to ask whether the breach of the obligation to refer could be excused.
91.      In my view, a court of last instance can indeed be excused for not referring, even if the Court of Justice a posteriori finds that it should have referred. That means that the Court of Justice’s finding in hindsight does not in itself result in an inexcusable breach of the obligation to refer.
92.      If the court has provided a reasonable explanation as to why, at the time when it was deciding, it considered that there was no such obligation in the circumstances of the case before it, its breach of the obligation to refer does not result in a sufficiently serious breach in the application of EU law. That leads me to the second novelty of Consorzio requiring that courts of last instance provide reasoning for their decisions not to refer.
C.      The importance of reasoning
93.      Even if I am of the opinion that a distinction between interpretation and application cannot be usefully made to relieve courts of last instance of the obligation to refer, I consider that such courts must be given sufficient freedom in the interpretation and application of EU law.
94.      As already recognised in van Gend & Loos, (62) national courts are part of the EU judiciary. Their position as EU courts has been accentuated and strengthened in more recent case-law. (63)
95.      In such a system, the relationship between the Court of Justice and national courts must be based on mutual trust. There is no reason, in principle, to doubt that courts of last instance will refer if they consider that this is important for the sake of uniformity of EU law. Therefore, I find the fear of non-uniformity that may result from breaches of the obligation to refer to be exaggerated. (64)
96.      In my view, the obligation to provide reasons, which is binding on national courts on the basis of Article 47 of the Charter of Fundamental Rights of the European Union (‘the Charter’) and which was strengthened in relation to stating reasons for not referring in Consorzio, is sufficient to compel courts to consider the interest in the uniformity of EU law when deciding whether they must refer in a particular case.
97.      As already stated, in Consorzio, the Court required the courts of last instance to provide reasons why they decided not to refer in the light of the three CILFIT situations. To my mind, such reasoning is an appropriate way in which the uniformity of EU law can be safeguarded while at the same time providing for the effective protection of individual rights.
98.      As I noted in my Opinion in Remling, (65) a proper statement of reasons explaining why a court of last instance did not refer may absolve that court from Köbler liability.
99.      What kind of statement of reasons can excuse a non-referral? Proper reasoning essentially requires that a last-instance court explain why it considers that an EU rule, in the light of the case-law interpreting it, does not leave a reasonable doubt that it applies to a particular set of facts in a particular way.
100. If the court explains why it finds such an application correct, that simultaneously demonstrates that that court did not consider that the Court of Justice or last-instance courts of other Member States would decide differently.
101. One cannot provide courts with a checklist of appropriate explanations, as this depends on the circumstances of each case. It is, however, possible to say what is not a proper statement of reasons, for example, an empty statement that the court has no doubt as to the correct application of EU law without explaining why, or a mechanical enumeration of relevant judgments of the Court of Justice, without any explanation as to why they lead the court to a particular outcome in the case.
102. The present case predates the introduction of the obligation on last-instance courts to provide reasons for their decision not to refer in the light of the CILFIT criteria, which had not been explicitly mentioned before Consorzio.
103. Nevertheless, the obligation to state reasons is, in any case, not based on Article 267 TFEU, but on Article 47 of the Charter, as part of the right to a fair trial, and exists to enable the parties in a case to understand the reasons for the judgment given. (66) In principle, a proper explanation as to why a rule was applied in a particular way would contain, even if not explicitly, an explanation as to why the court did not refer.
104. Thus, even if in hindsight, as in the present case, the Court of Justice might consider that a last-instance court should have referred, that does not mean that its (now evident) breach of the obligation to refer automatically entails that the breach of EU law conferring rights on individuals is sufficiently serious.
105. Proper explanation for non-referral can excuse the breach of the obligation to refer and would not lead to a sufficiently serious breach.
106. Such an interpretation of the interaction between the breach of the EU rule conferring rights and the breach of the obligation to refer is consistent with the outcome in Köbler. In that case, the Court considered that the Austrian court of last instance incorrectly applied EU law and that it should have maintained its request for a preliminary ruling. Nevertheless, the Court found the decision not to refer excusable because the court incorrectly read the relevant judgment of the Court. As a result, the Court found that there was no sufficiently serious breach. (67)
107. To conclude this part, if a court of last instance provides a reasonable explanation as to why it has applied EU law, including pertinent case-law, in the way it did, then even if in hindsight such an application is considered incorrect, the court’s decision not to refer can be excused and not lead to the finding of a sufficiently serious breach for the purposes of State liability.
D.      Application to the present case
108. As regards the present case, I observe that, when the solution of a case depends on the application of highly fact-dependent concepts like the concept of a ‘transfer of a business’, it is possible that two judges conclude differently in the same circumstances as to whether a transfer of a business has taken place. (68)
109. Indeed, different conclusions were reached by the Portuguese Supreme Court in the 2009 judgment and the Court of Justice in Ferreira I.
110. Provided that the Court of Justice confirms, in answering the first question, that the Portuguese Supreme Court incorrectly applied the EU concept of a ‘transfer of a business’, the decision of that court not to refer in the 2009 judgment might contribute to finding that incorrect application to be a sufficiently serious breach. That would be so, however, only if that court did not provide an adequate explanation in the 2009 judgment as to why it considered that the case-law of the Court led it to conclude that a transfer of a business had not occurred in the circumstances of the case.
111. Even if the Court of Justice considered in Ferreira I that the Portuguese Supreme Court should have referred, that does not mean that such a breach cannot be excused. In Ferreira I, the Court was not asked how the breach of the obligation to refer contributes to the finding of a sufficiently serious breach for the purposes of State liability.
112. It seems to me that the Portuguese Supreme Court did take into consideration the pertinent case-law of the Court of Justice, and that it explained how that case-law led it to the conclusion that a transfer of a business did not occur in the particular circumstances of the case (see point 13 of this Opinion). (69) That is, however, for the referring court to verify based on the explanation contained in the 2009 judgment.
113. It also seems to me that it was precisely because of that case-law of the Court of Justice that the Portuguese Supreme Court considered that a preliminary reference was not necessary. It took the view that the concept of a ‘transfer of a business’ was sufficiently clarified through the Court’s interpretation so as to resolve the case.
114. The Court of Justice, however, considered in Ferreira I that one of the reasons why the Portuguese Supreme Court was obliged to refer was precisely the fact that other national courts found the concept of a ‘transfer of a business’ complex and had often referred (see point 19 of this Opinion). Therefore, somewhat paradoxically, the Court of Justice considered that the many interpretations it provided in different cases were the reason for the Portuguese Supreme Court to refer again. That court, on the contrary, considered that those interpretations were the reason why it did not need to refer, as it found that the existing case-law informed it sufficiently to apply that concept to the novel circumstances of the case.
115. The Portuguese Supreme Court’s position seems to me to be an acceptable explanation as to why it considered that it need not refer. However, that is so, provided that it has indeed explained why the existing case-law clarified the concept of a ‘transfer of a business’ beyond any reasonable doubt for the purposes of its application to the circumstances of the case.
IV.    Conclusion
116. In the light of all of the foregoing considerations, I propose that the Court should answer the third question referred by the Supremo Tribunal de Justiça (Supreme Court, Portugal) as follows:
For the purpose of establishing whether a judicial error by a court of last instance represents a sufficiently serious breach to engage State liability, a breach of the obligation to refer is only a factor to be taken into consideration. A breach of the obligation to refer may contribute to finding that the breach of EU law conferring rights is sufficiently serious, but cannot in itself result in State liability.
Whether a court of last instance incorrectly interpreted or incorrectly applied EU law conferring rights on individuals, the failure to refer might lead to a sufficiently serious breach for the purposes of State liability.
If a court of last instance provides adequate reasoning as to why it has applied EU law, including pertinent case-law, in the way it did, then the court’s decision not to refer can be excused and not lead to the finding of a sufficiently serious breach for the purposes of State liability.
1      Original language: English.
2      Judgment of 30 September 2003 (C‑224/01, ‘Köbler’, EU:C:2003:513).
3      Judgment of 6 October 1982, Cilfit and Others (283/81, ‘CILFIT’, EU:C:1982:335).
4      Judgment of 6 October 2021, Consorzio Italian Management and Catania Multiservizi (C‑561/19, ‘Consorzio’, EU:C:2021:799).
5      Council Directive of 14 February 1977 on the approximation of the laws of the Member States relating to the safeguarding of employees’ rights in the event of transfers of undertakings, businesses or parts of businesses (OJ 1977 L 61, p. 26). That directive was amended by Council Directive 98/50/EC of 29 June 1998 (OJ 1998 L 201, p. 88).
6      Council Directive of 12 March 2001 on the approximation of the laws of the Member States relating to the safeguarding of employees’ rights in the event of transfers of undertakings, businesses or parts of undertakings or businesses (OJ 2001 L 82, p. 16).
7      See, in that regard, Articles 3 and 4 and the second recital of Directive 77/187; Articles 3 and 4 and recital 3 of Directive 2001/23.
8      See, in that regard, Article 1(1)(b) and recitals 1, 7 and 8 of Directive 2001/23.
9      The length of the proceedings led to a judgment of the European Court of Human Rights (ECtHR), finding a violation of Article 6(1) of the European Convention on Human Rights (ECHR) for exceeding a reasonable time, as well as a violation of Article 13 ECHR based on the lack of an effective remedy for complaining about the excessive duration of the proceedings. See ECtHR, 22 May 2012, Ferreira da Silva e Brito and Others v. Portugal, CE:ECHR:2012:0522JUD004627309.
10      See, in particular, pp. 74 to 79 (read with the aid of machine translation).
11      See, in particular, pp. 49 to 57 (read with the aid of machine translation).
12      See, in particular, pp. 157 to 181 (read with the aid of machine translation). That judgment is summarised in the order for reference in the present case.
13      According to the 2009 judgment, the Portuguese Supreme Court essentially decided as follows. First, that court set out the legislative framework governing a transfer of a business, taking into account the objectives of the national legislation and the provisions of Directives 77/187 and 2001/23, along with the case-law of the Court of Justice regarding the assessment to be undertaken as to whether there has been a transfer of a business. Second, that court, having regard to the criteria laid down by national and EU law, carried out that assessment in the case at hand. It considered, inter alia, that there was no formal act of transfer between AIA and TAP, nor was there a de facto transfer of several separate elements reorganised within TAP as an autonomous business entity, and even assuming that a separate transfer of assets could make it possible to reconstitute a business as an economic unity within the recipient, this had not been demonstrated in that case. It also took into consideration various elements, finding that none were conclusive as to the existence of a transfer of a business from AIA to TAP and referred to case-law of the Court of Justice in that regard.
14      According to the 2009 judgment, the Portuguese Supreme Court essentially reasoned as follows. First, in view of the content of the directives concerned, their interpretation by the Court of Justice and the elements of the case at hand, there was no relevant doubt as to the interpretation which would require a preliminary reference. Second, the Court of Justice had established a body of settled case-law on the interpretation of the concept of a ‘transfer of a business’, given that Directive 2001/23 reflected the consolidation of concepts arising from that case-law and that those concepts were now clear in terms of judicial (EU and national) interpretation, which meant that it was not necessary to consult the Court of Justice beforehand. Third, the question of the compatibility of certain provisions of national law with that directive could not be the subject of a preliminary reference. Fourth, it was not for the Court of Justice to determine whether a rule of EU law was applicable to a given situation before the national courts of the various Member States; thus, the question whether the Court of Justice’s interpretation of Directives 77/187 and 2001/23 was consistent with the interpretation and application of national legislation on a transfer of a business carried out by the Lisbon Court of Appeal could not be referred to the Court of Justice.
15      C‑160/14, EU:C:2015:565.
16      Ferreira I (paragraph 35).
17      See Ferreira I (paragraphs 29 to 31).
18      Judgment of 12 February 2009 (C‑466/07, ‘Klarenberg’, EU:C:2009:85). To recall, the 2009 judgment had been delivered on 25 February 2009.
19      See Ferreira I (paragraphs 32 to 34).
20      See
Ferreira I (paragraph 45). In that respect, in paragraphs 41 and 42 of that judgment, the Court made clear that the mere fact that lower courts had given conflicting decisions was not conclusive in triggering the obligation to refer. This was in line with the judgment of 9 September 2015, X and van Dijk (C‑72/14 and C‑197/14, EU:C:2015:564, paragraphs 52 to 63), decided by the Court on the same day and by the same chamber as Ferreira I, where the Court found that there is no obligation to refer on the part of a last-instance court based solely on the fact that a lower court has made a preliminary reference in a similar case, nor is the last-instance court required to wait until the answer to that question has been given.
21      Ferreira I (paragraphs 43 and 44).
22      See in particular pp. 203 to 215 (read with the aid of machine translation).
23      According to that judgment, the Lisbon District Court considered that there was no error in the interpretation of the concept of a ‘transfer of a business’ under Directive 2001/23. It emphasised, inter alia, that the Portuguese Supreme Court had developed a thorough reasoning taking into account EU law, and had recognised that, according to the case-law of the Court of Justice, it was necessary to undertake an overall analysis of the circumstances of the case. Nor could it be said that the Portuguese Supreme Court was wrong in so far as it did not refer to the Klarenberg judgment, since it had addressed the issue in a general way. That court also found that the Portuguese Supreme Court had set out the reasons for its decision not to make a preliminary reference in a logical and coherent manner and, even if the decision was incorrect based on information known later, that error could not be characterised as a sufficiently serious breach of EU law.
24      See in particular pp. 318 to 382 (read with the aid of machine translation).
25      According to that judgment, the Lisbon Court of Appeal found that, in the light of the overall assessment that must be made of all the factors and circumstances in accordance with the case-law of the Court of Justice, the Portuguese Supreme Court did not incorrectly interpret the concept of a ‘transfer of a business’. It emphasised, inter alia, that the Klarenberg judgment did not alter that assessment, and that it is the national court that has jurisdiction to decide whether a transfer of a business takes place in a specific case. It also considered that the Portuguese Supreme Court had breached the obligation to refer by incorrectly assessing whether there were grounds for dispensing with that obligation, but that this was not manifest in the specific circumstances of the case. It pointed out, in particular, that the Portuguese Supreme Court had taken into consideration the relevant provisions of the directives in question and the case-law of the Court of Justice relating to the concept of a ‘transfer of a business’.
26      In that respect, the referring court notes that, in Köbler and the judgment of 28 July 2016, Tomášová (C‑168/15, EU:C:2016:602), the Court determined that there had not been a sufficiently serious breach of EU law.
27      According to Article 23(3) of Decree-Law No 64-A/89 of 27 February 1989 establishing the legal rules governing the termination of individual contracts of employment and the conclusion and expiry of fixed-term contracts of employment, the taking of compensation by employees whose contract was terminated on account of collective redundancy equated to acceptance of the dismissal.
28      To borrow the expression from the Opinion of Advocate General Bobek in Hochtief Solutions Magyarországi Fióktelepe (C‑620/17, EU:C:2019:340, point 131).
29      See Köbler (in particular paragraphs 30 to 50).
30      See, in particular, judgments of 19 November 1991, Francovich and Others (C‑6/90 and C‑9/90, EU:C:1991:428), and of 5 March 1996, Brasserie du pêcheur and Factortame (C‑46/93 and C‑48/93, EU:C:1996:79).
31      See Köbler (paragraphs 51 and 52).
32      See, by analogy, in relation to EU non-contractual liability, judgment of 10 September 2019, HTTS v Council (C‑123/18 P, EU:C:2019:694, paragraph 34), where the Court recognised that ‘the requirement that there be a sufficiently serious breach of a rule of EU law stems from the need to strike a balance between, on the one hand, the protection of individuals against unlawful conduct of the institutions and, on the other, the leeway that must be accorded to the institutions in order not to paralyse action by them’.
33      Köbler (paragraph 53) (emphasis added). The Court repeated this in other cases concerning State liability attributable to national courts of last instance. See, for example, judgments of 13 June 2006, Traghetti del Mediterraneo (C‑173/03, EU:C:2006:391, paragraphs 32 and 42); of 28 July 2016, Tomášová (C‑168/15, EU:C:2016:602, paragraph 24); and of 29 July 2019, Hochtief Solutions Magyarországi Fióktelepe (C‑620/17, EU:C:2019:630, paragraph 41).
34      See Köbler (paragraph 55). Similar factors were also set out in subsequent judgments relating to State liability attributable to national courts of last instance. See, for example, judgments of 13 June 2006, Traghetti del Mediterraneo (C‑173/03, EU:C:2006:391, paragraph 43), and of 28 July 2016, Tomášová (C‑168/15, EU:C:2016:602, paragraph 25).
35      See, in that regard, judgment of 5 March 1996, Brasserie du pêcheur and Factortame (C‑46/93 and C‑48/93, EU:C:1996:79, paragraph 56).
36      For a salient example, see judgment of 24 September 1998, Brinkmann (C‑319/96, EU:C:1998:429, in particular paragraphs 30 to 33), in which the Court considered that the incorrect application of an EU directive in the field of taxation by a national administrative body, which wrongly classified the taxable product, did not constitute a sufficiently serious breach.
37      Therefore, even though all the factors are listed together, the factor relating to the excusable or inexcusable nature of the breach seems to be the central one, which encapsulates the others. See, to that effect, Opinions of Advocate General Léger in Köbler (C‑224/01, EU:C:2003:207, point 139), and in Traghetti del Mediterraneo (C‑173/03, EU:C:2005:602, point 71).
38      That is how I understand the Court’s statement in Köbler (paragraph 56) that ‘in any event, an infringement of [EU] law will be sufficiently serious where the decision concerned was made in manifest breach of the case-law of the Court in the matter’.
39      See, in that regard, my Opinion in Remling (C‑767/23, EU:C:2025:486, points 46 and 47).
40      As the obligation to refer was imposed in the general interest of ensuring the uniformity of EU law, it may be enforced by an infringement action under Articles 258 to 260 TFEU. See, for example, judgments of 4 October 2018, Commission v France (Advance payment) (C‑416/17, EU:C:2018:811), and of 14 March 2024, Commission v United Kingdom (Judgment of the Supreme Court) (C‑516/22, EU:C:2024:231).
41      See, in that respect, the recent judgment of the EFTA Court of 5 June 2025 in Dartride AS v Norwegian State (E-25/24, paragraph 36), in which that court stated: ‘The third paragraph of Article 267 TFEU thus plays a role in the assessment of the seriousness of the breach rather than being one of the constituent elements for the existence of liability …’
42      See CILFIT (paragraphs 10, 13, 14 and 16).
43      See CILFIT (paragraphs 13 and 14).
44      CILFIT (paragraph 16). I have discussed the three CILFIT situations in more detail in my Opinion in Remling (C‑767/23, EU:C:2025:486, points 24 to 35).
45      In that respect, in my understanding, ‘acte clair’ does not mean that a clear EU rule can mechanically be applied to the circumstances of the case. Rather, it means that a court of last instance has to interpret the applicable EU law in accordance with the interpretative rules used by the Court (the CILFIT criteria) and decide whether it leaves scope for any reasonable doubt that the Court, relying on the same interpretative rules, may come to a different conclusion. See, in that respect, Petrić, D., ‘How to make a unicorn or “there never was an ‘acte clair’ in EU law”: Some remarks about Case C‑561/19 Consorzio Italian Management’, Croatian Yearbook of European Law & Policy, Vol. 17, 2021, pp. 307-328.
46      Compare CILFIT (paragraphs 16 and 21), with Consorzio (paragraphs 33, 39 and 66).
47      See Consorzio (paragraph 51). See further my Opinion in Remling (C‑767/23, EU:C:2025:486, in particular points 43 to 61), in which I discussed the reasons and the legal basis for such an obligation.
48      See Opinion of Advocate General Bobek in Consorzio Italian Management and Catania Multiservizi (C‑561/19, EU:C:2021:291, in particular points 131 to 181).
49      In his Opinion in Consorzio Italian Management and Catania Multiservizi (C‑561/19, EU:C:2021:291, point 134), Advocate General Bobek proposed that a national court of last instance only has an obligation to refer if the case raises: (i) a general issue of interpretation of EU law (as opposed to its application); (ii) to which there is objectively more than one reasonably possible interpretation; (iii) for which the answer cannot be inferred from the existing case-law of the Court (or with regard to which the referring court wishes to depart from that case-law).
50      See, for example, Broberg, M. and Fenger, N., ‘If you love somebody set them free: On the Court of Justice’s revision of the acte clair doctrine’, Common Market Law Review, Vol. 59, No 3, 2022, pp. 711-738, in particular pp. 735-736, noting that by the change in wording, the Court supported the reading according to which the aim of Article 267 TFEU is to ensure uniform interpretation, and not to involve the Court in each and every difficult application of EU law by last-instance courts.
51      See, for example, Cecchetti, L. and Gallo, D., ‘The unwritten exceptions to the duty to refer after Consorzio Italian Management II: “CILFIT Strategy” 2.0 and its loopholes’, Review of European Administrative Law, Vol. 15, No 3, 2022, pp. 29-61, in particular pp. 52-53.
52      For example, Broberg, M. and Fenger, N., Broberg and Fenger on Preliminary References to the European Court of Justice, 3rd ed., Oxford University Press, Oxford, 2021, pp. 216-218, suggest that Ferreira I is an example of the application of EU law.
53      One may also understand the Court’s ruling in Ferreira I as the application of EU law, as the Court interpreted the concept of a ‘transfer of a business’ in the specific circumstances of that case (see point 17 of this Opinion). However, as the division of tasks in the preliminary ruling procedure is described so that the Court of Justice interprets, and the national courts apply, EU law, it is likely that the Court’s answer provided in that case would be described as the interpretation of EU law.
54      See point 19 of this Opinion.
55      See Opinion of Advocate General Capotorti in Cilfit and Others (283/81, EU:C:1982:267, point 4; 1982 ECR 3432, in particular p. 3435). He used such an argument to reject the theory of the ‘acte clair’, understood in the sense that if a rule is clear, there is no need to interpret it, but merely to apply it.
56      In his Opinion in Consorzio Italian Management and Catania Multiservizi (C‑561/19, EU:C:2021:291, point 149), Advocate General Bobek indeed recognised this inconvenience, stating that he was not suggesting that ‘we get rid of one unicorn in order for it to be replaced immediately by another’.
57      Regulation (EC) No 261/2004 of the European Parliament and of the Council of 11 February 2004 establishing common rules on compensation and assistance to passengers in the event of denied boarding and of cancellation or long delay of flights, and repealing Regulation (EEC) No 295/91 (OJ 2004 L 46, p. 1).
58      Opinion of Advocate General Bobek in Consorzio Italian Management and Catania Multiservizi (C‑561/19, EU:C:2021:291, point 140).
59      See Opinion of Advocate General Bobek in Consorzio Italian Management and Catania Multiservizi (C‑561/19, EU:C:2021:291, point 140, footnote 115) (referring, in particular, to the judgment of 22 December 2008, Wallentin-Hermann (C‑549/07, EU:C:2008:771, paragraph 23)).
60      Today, we know that a collision of a plane with a bird is an extraordinary circumstance, as the Court held in the judgment of 4 May 2017, Pešková and Peška (C‑315/15, EU:C:2017:342, paragraph 26).
61      That does not mean that the Court cannot, as a matter of its judicial policy, decide to provide a more general answer when asked to interpret EU law. See, in that regard, Opinion of Advocate General Jacobs in Wiener SI (C-338/95, EU:C:1997:352, in particular points 8 to 21 and 48), recommending the latter approach, among other things, when considering the Court’s interpretation of the concept of a ‘transfer of a business’.
62      Judgment of 5 February 1963 (26/62, EU:C:1963:1).
63      See, for example, judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses (C‑64/16, EU:C:2018:117).
64      I agree, however, that it might have been different at the time when CILFIT was decided. See, for example, Rasmussen, H., ‘The European Court’s acte clair strategy in CILFIT Or: acte clair, of course! But what does it mean?’, European Law Review, Vol. 40, No 4, 2015, pp. 475-489 (this article reproduces the older article published in the European Law Review, Vol. 9, 1984, pp. 242-259).
65      See my Opinion in Remling (C‑767/23, EU:C:2025:486, point 50). See also Krommendijk, J., ‘“Open sesame!”: Improving access to the ECJ by requiring national courts to reason their refusals to refer’, European Law Journal, Vol. 42, No 1, 2017, pp. 46-62, in particular p. 59, footnote 104, noting that: ‘It is also easier for the national court handling a Köbler claim to examine whether the court has indeed fulfilled the criteria for liability. It does not seem unreasonable to assume that when national courts provide reasons for their refusals to refer, they can more easily avoid liability, because of the absence of bad faith on their part.’
66      See my Opinion in Remling (C‑767/23, EU:C:2025:486, points 52 and 59).
67      See Köbler (paragraphs 123 and 124).
68      See, for example, Beltzer, R.M., ‘The Transfer of Undertakings and the Importance of Taking Over Personnel – A Vicious Circle?’, International Journal of Comparative Labour Law and Industrial Relations, Vol. 23, No 1, 2007, pp. 139-155, in particular pp. 141-142, who considered that, even if the Court has provided some interpretative factors, ‘it is possible, for instance, for two judges to rule differently on the same factual information in answering the question whether a transfer of undertaking has taken place. It is virtually impossible to present that subjectivity to a European court, since the weighing of the Spijkers factors is a question of fact-finding rather than a legal exercise.’
69      In that respect, omitting the Klarenberg judgment, which was delivered by the Court only days before the 2009 judgment, does not make a significant difference in assessing whether the Portuguese Supreme Court could have considered that a preliminary reference was not necessary. That judgment was only one in the series of judgments explaining the concept of a ‘transfer of a business’ in a different set of circumstances.