Binding Force, Temporal Reach, and Post-Judgment Remedies
The preliminary ruling – the Court of Justice’s response to a question referred by a national court under Article 267 TFEU – constitutes the operative output of the preliminary reference procedure. While the mechanics of making a reference are tolerably well understood, it is the consequences of the resulting ruling that generate the most acute difficulties in practice. These consequences determine whether the procedure yields tangible results for the parties to the underlying dispute: the undertaking contesting a tax assessment, the consumer challenging an unfair contractual term, the taxpayer seeking a refund.
A threshold clarification is essential. The Court of Justice does not annul or reverse national court judgments. It does not adjudicate questions of fact. It does not apply law to the circumstances of a particular case. A preliminary ruling furnishes the authoritative interpretation of a provision of EU law – or, where relevant, a determination as to the validity of secondary legislation – which the referring court is then bound to apply in disposing of the case before it. The final judgment in the dispute remains, at all times, the province of the national court.
Grasping this institutional architecture – the division of competence between the Court of Justice and the national judiciary – is a prerequisite for any effective deployment of EU law in domestic litigation.
The Binding Force of Preliminary Rulings
A preliminary ruling is binding, in the first instance, upon the referring court. That court is obligated to apply the interpretation furnished by the CJEU to the resolution of the pending dispute. As the Polish Supreme Court (*Sąd Najwyższy*) observed in its order of 25 January 2018 (IV CSK 664/14): “A judgment of the Court of Justice of the European Union delivered pursuant to Article 267 TFEU is binding only in the case in which the court addressed a request for a preliminary ruling to the Court of Justice.”
The Supreme Court was quick to add, however, that “a question on the interpretation of EU law provisions should be referred to the Court of Justice in every case in which such interpretation is necessary. The Court’s judgment is binding in the case in which the referring court posed the question, yet all other national courts take it into account.”
This distinction between formal *inter partes* binding force and *de facto erga omnes* effect lies at the heart of the preliminary ruling’s systemic significance. In strict doctrinal terms, the ruling binds the referring court and any other courts adjudicating the same case on further appeal. In practical terms, however, the interpretation adopted by the CJEU is to be followed by all national courts confronted with analogous issues – not because they are formally bound by the ruling as such, but because the doctrine of *acte éclairé* means that the question has been authoritatively resolved: were another court to harbour doubts on the same point, it would itself be obligated to refer (or, in the case of a lower court, would lack grounds for a reference, the question having already been answered).
The Supreme Administrative Court (*Naczelny Sąd Administracyjny*) articulated this with notable precision in its judgment of 5 April 2017 (I FSK 1423/15): “The judgments of the Court of Justice of the EU have the character of precedents that shape EU interpretive standards and resolve uncertainties through authoritative interpretation. In this context, they must be taken into account in the course of adjudication to the extent that they bear upon the determination of the case.”
The practical corollary is significant. A preliminary ruling delivered in a dispute involving a different taxpayer, a different consumer, or a different employer carries direct implications for the legal position of persons in analogous circumstances – notwithstanding the absence of formal binding force. A national court that is cognisant of the CJEU’s interpretation and disregards it risks a finding of infringement of EU law.
Declaratory Nature and Temporal Reach: Interpretation or Lawmaking?
Preliminary rulings are, in principle, declaratory. The Court of Justice does not create new norms; it declares the meaning that a provision of EU law has borne since its entry into force. The interpretation rendered in a preliminary ruling operates retroactively: the provision has always meant what the CJEU says it means.
The practical ramifications are far-reaching. Where the Court of Justice determines that a particular national tax is incompatible with the VATVAT Directive, that interpretation takes effect from the date the directive entered into force – not from the date of the judgment. In Case C-331/13 (judgment of 15 October 2014), the CJEU confirmed that EU law “precludes a system for the refund of a tax levied in breach of EU law” – the obligation to refund had existed from the outset, and the ruling merely confirmed as much.
The Court may, however, in exceptional circumstances limit the temporal effects of its ruling. In Case C-313/05 (Brzeziński, judgment of 18 January 2007), the Court held that “only exceptionally may the Court, applying the general principle of legal certainty inherent in the legal order, decide to restrict the possibility for any person concerned of relying on a provision which it has interpreted with a view to calling into question legal relationships established in good faith” – adding that “the financial consequences which might ensue for a Member State from a preliminary ruling do not in themselves justify limiting the temporal effects of the ruling.” Temporal limitation remains an extraordinary remedy: the Court applies it only where retroactive application would give rise to serious economic disruption, and the budgetary argument alone is insufficient.
Preliminary Rulings and Res Judicata: An Enduring Tension
Among the most intractable problems of EU procedural law is the relationship between preliminary rulings and the national law principle of *res judicata*. The question presents itself thus: what is the legal position where a final national judgment rested upon an interpretation of EU law that the CJEU subsequently repudiated in a preliminary ruling delivered in a different case?
The Court of Justice has approached this problem from two directions.
On the one hand, the CJEU has consistently required national courts to apply the correct interpretation of EU law even at the expense of procedural rules that would otherwise preclude re-examination. In its judgment of 18 December 2025 (Case C-320/24), the Court held that Directive 93/13 “precludes national rules under which the application of the principle of *res judicata* prevents a national court, to which a case has been referred back following a cassation appeal, from examining of its own motion the invalidity of a potentially unfair contractual term” – even where the consumer did not raise the issue at earlier stages of the proceedings.
On the other hand, once proceedings have concluded with a final judgment, the principle of legal certainty generally protects the stability of judicial determinations. The CJEU has not mandated the wholesale reopening of final judgments on the basis of subsequent preliminary rulings.
This doctrinal tension remains unresolved in any definitive sense and continues to generate litigation across the Member States.
Requesting a Preliminary Reference: Persuading the National Court
A preliminary ruling can only be delivered if the national court submits a reference. And a court will submit a reference only where a party has effectively demonstrated why one is warranted. The following considerations are integral to a sound litigation strategy.
Formulate a precise question. The Court of Justice responds to specific questions concerning the interpretation of EU law – not to generalized expressions of uncertainty. The most effective application identifies the particular EU provision at issue, describes the factual matrix of the case, explains the interpretive difficulty that has arisen, and demonstrates why the CJEU’s guidance is necessary for the resolution of the dispute. The judgment of 3 April 2025 (Case C-701/23) elaborates the formal requirements of the order for reference, by reference to paragraph 15 of the Court’s Recommendations to national courts.
Negate the application of *acte clair* and *acte éclairé*. A court – particularly one of last resort – may decline to refer if it considers the interpretation to be manifest or the point to have been settled by prior CJEU authority. The task of counsel is to demonstrate that the doubt is genuine: that domestic case law is divided, that other Member States interpret the same provision differently, or that the existing body of CJEU jurisprudence does not address the specific features of the case at hand. The Court of Justice itself affirmed in Case C-160/14 (judgment of 9 September 2015) that the obligation to refer arises with particular force where “there have been divergent decisions concerning the interpretation of that concept by lower courts.” This is an argument that counsel may deploy directly.
Establish the nexus with the disposition of the case. A preliminary reference must be necessary for the delivery of judgment in the specific proceedings. The Court of Justice rejects references where the EU provision in question is inapplicable to the main proceedings (Case C-419/24, judgment of 19 June 2025) or where the dispute can be resolved exclusively on the basis of national law.
Invoke the court’s autonomous right to refer. Even where a lower court is formally bound by the interpretation of a higher court under domestic law, Article 267 TFEU safeguards its independent power to make a preliminary reference. The Court of Justice confirmed this in Case C-689/13 (judgment of 5 April 2016): a chamber of a court of last resort cannot be precluded from making a reference merely because the full court of the same institution has adopted a different interpretation.
Consider early referral. A preliminary reference may be submitted at any stage of the proceedings. A court of first instance enjoys the same power as the Supreme Court – though it bears no corresponding obligation. Early referral may be strategically advantageous: a stay at first instance is less costly, in both temporal and financial terms, than a protracted appellate trajectory culminating in a reference only at the cassation stage.
Post-Judgment Relief: Reopening Proceedings on the Basis of a CJEU Ruling
The preliminary reference procedure presupposes the pendency of proceedings. But what remedies are available where an adverse final judgment preceded the delivery of a CJEU ruling demonstrating that the national court misapplied EU law?
Polish procedural law provides for the reopening of proceedings, and the Supreme Administrative Court has confirmed that a CJEU ruling may constitute a ground for such reopening.
In administrative cases, Article 272(3) of the Law on Proceedings before Administrative Courts (*Prawo o postępowaniu przed sądami administracyjnymi*) permits a petition for reopening “where such a need arises from a ruling of an international body acting on the basis of a ratified international agreement.” In its resolution of 16 October 2017 (I FPS 1/17), the Supreme Administrative Court held that a CJEU judgment delivered in a preliminary ruling in a different case may constitute a ground for the reopening of administrative court proceedings, provided it demonstrates that the final Polish judgment rested on an erroneous interpretation of EU law.
In civil cases, an analogous basis is furnished by Article 403 of the Code of Civil Procedure (*Kodeks postępowania cywilnego*), and case law has extended its scope to encompass CJEU judgments.
This is a matter of considerable practical importance for undertakings and individuals who have exhausted their appellate remedies in EU law disputes. Even after a final judgment, a legal pathway remains – not a further preliminary reference (for no proceedings are pending), but the reopening of concluded proceedings on the basis of a CJEU ruling.
The Duty of Consistent Interpretation: Preliminary Rulings and National Law
Preliminary rulings do not operate in isolation. Even absent a direct invocation of a specific CJEU judgment, national courts are under a duty to interpret domestic law in a manner consistent with EU law – within the methodological limits that the canons of interpretation permit.
The Polish Supreme Court illustrated this obligation in its order of 25 January 2018 (IV CSK 664/14), which concerned the cross-border transfer of a company’s registered office to Luxembourg. Although the national provisions found by the CJEU to infringe the freedom of establishment had not been formally repealed, the Supreme Court held that “the registry court is obligated to disapply the provisions of Polish law requiring the completion of a full liquidation procedure and to construe the remaining provisions by applying the directive of EU-consistent interpretation, overriding the rules of literal construction.”
The signal is unmistakable: a preliminary ruling alters the manner in which national courts read domestic law – irrespective of whether the legislature has undertaken or declined to amend the relevant provisions.
The CJEU pressed this principle further in Case C-689/13 (judgment of 5 April 2016), where it held that, upon receiving the Court’s answer to a preliminary question, “a chamber of a court of last resort must itself take all steps necessary to ensure that the interpretation of EU law is implemented.” The obligation to give effect to a preliminary ruling is accordingly not abstract – it devolves upon the specific judicial formation adjudicating the specific case.
Preliminary Rulings of 2025–2026: Selected Developments of Practical Significance
The preliminary ruling jurisprudence of recent months furnishes practitioners and their advisors with material of direct practical relevance.
Tax law – VAT and excise. In Case C-232/24 (judgment of 23 October 2025), the Court of Justice addressed the VAT treatment of factoring arrangements, holding that the financing commission and the handling fee constitute consideration for a single indivisible debt collection service subject to VAT. In Case C-234/24 (same date), the Court ruled on the conditions for VAT refunds in the context of intra-Community supplies. In Case C-121/24 (judgment of 11 December 2025), it confirmed the permissibility of joint and several liability of the recipient for the supplier’s unpaid VAT, provided the recipient knew or ought to have known that the person liable would not pay the tax.
Consumer protection – WIBOR and unfair terms. The judgment of 12 February 2026 (Case C-471/24) clarified the transparency requirements applicable to variable-rate mortgage contracts pegged to the WIBOR benchmark. The judgment of 18 December 2025 (Case C-320/24) broke through the *res judicata* barrier in consumer protection cases. The judgment of 11 December 2025 (Case C-767/24) held that a consumer’s set-off declaration cannot be treated as an implied waiver of the defence of limitation against the bank.
Family foundation taxation. The judgment of 13 November 2025 (Case C-142/24) addressed differential taxation of asset transfers to family foundations depending on their residence status – a question of immediate relevance to Polish founders contemplating cross-border structures.
Employment law – posting of workers. The judgment of 11 December 2025 (Case C-485/24) clarified the criteria for determining the applicable law where a worker is posted to a new habitual place of work.
Late payments – set-off and statutory interest. The judgment of 18 December 2025 (Case C-481/24) confirmed that a declaration of set-off submitted after the contractual payment deadline may, by virtue of its retroactive effect, extinguish the creditor’s entitlement to statutory interest for late payment.
Each of these rulings formally binds only the referring court, yet their interpretive authority extends – through the operation of *acte éclairé* – to all national courts confronted with analogous questions.
How We Can Assist
Skarbiec Law Firm conducts litigation in which the consequences of preliminary rulings bear directly upon the client’s legal position. We advise on whether a specific CJEU ruling opens the path to the reopening of concluded proceedings, prepare applications for preliminary references, and represent clients before national courts at every stage – from first instance through to the Supreme Court and the Supreme Administrative Court.
If your dispute has a European Union law dimension, we invite you to contact us.
