Introduction
On 24 September 2026, the Court of Justice of the European Union (Third Chamber) delivered its judgment in Case C-176/25, IU v BT, a reference for a preliminary ruling arising in the area of freedom, security and justice. The case sits at the intersection of two foundational instruments of European private international law: Regulation (EC) No 593/2008, commonly known as Rome I, which governs the law applicable to contractual obligations, and Regulation (EC) No 864/2007, commonly known as Rome II, which governs the law applicable to non-contractual obligations.
The central question referred to the Court concerned a copyright infringement scenario in which the defendant did not merely contest the alleged infringement itself, but went further and challenged the formal validity of the assignment contract through which the claimant purported to hold exclusive rights to use works protected by copyright. The Court was therefore asked to determine whether that incidental challenge to the assignment contract constitutes a 'contractual matter' for the purposes of the applicable-law framework established by Rome I, or whether it remains governed by the non-contractual logic of Rome II.
This judgment is significant for practitioners and courts across the European Union because it clarifies how the two Rome regulations interact in litigation where a non-contractual claim — here, a copyright infringement action — gives rise to an ancillary contractual question that is decisive for the outcome of the case.
Legal and factual background
The dispute in IU v BT originated from an alleged infringement, by a third party (BT), of rights that the claimant (IU) asserted were exclusive rights to use works protected by copyright. The claimant's standing to bring the infringement action depended on the validity of an assignment contract between IU, as assignee, and the original author of the works.
The defendant challenged that foundation by contesting the formal validity of the assignment contract. This procedural move raised an immediate conflict-of-laws question: should the law applicable to that challenge be determined under Rome I, because the challenge concerns a contract, or under Rome II, because the primary claim is one of non-contractual liability for copyright infringement?
The referring court sought guidance from the Court of Justice through the preliminary ruling mechanism, reflecting the broader importance of the question for judicial cooperation in civil matters within the European Union. The case therefore illustrates how a single set of facts can engage both Rome regulations simultaneously, requiring a principled method for allocating each issue to the correct instrument.
The Rome I and Rome II framework
Regulation (EC) No 593/2008 (Rome I) establishes uniform rules for determining the law applicable to contractual obligations in civil and commercial matters. It applies where there is a conflict of laws, and it covers the formation, validity, and effects of contracts, including questions of formal validity.
Regulation (EC) No 864/2007 (Rome II) performs an analogous function for non-contractual obligations, including those arising from intellectual property infringements. Under Rome II, the law applicable to a non-contractual obligation arising from an infringement of an intellectual property right is generally the law of the country for which protection is claimed.
The two regulations are designed to be complementary and mutually exclusive in their scope: an obligation is either contractual or non-contractual, and the characterisation of each issue determines which regulation supplies the applicable law. When litigation involves both a non-contractual primary claim and an incidental contractual question, courts must carefully disaggregate the issues rather than applying a single regulation to the entirety of the dispute.
The Court's analysis of the characterisation question
The Court of Justice was asked to rule on whether the defendant's challenge to the formal validity of the assignment contract between the assignee (IU) and the author falls to be treated as a contractual matter, thereby engaging Rome I, even though the primary action is a non-contractual copyright infringement claim governed by Rome II.
The judgment addresses the nature of the issue raised by the defendant's challenge. The formal validity of a contract — that is, whether the contract satisfies the requirements of form prescribed by the applicable law — is a question that is intrinsically linked to the contract itself. It concerns the existence and regularity of the contractual instrument rather than the consequences of the alleged infringement.
By framing the question in this way, the Court's analysis in Case C-176/25 reinforces the principle that the applicable-law determination must follow the legal nature of each discrete issue in the proceedings, not the overall classification of the action. A defendant who raises the formal invalidity of an assignment contract as a defence in infringement proceedings is, in substance, raising a contractual question, and that question must be resolved by reference to the law designated by Rome I.
Implications for judicial cooperation in civil matters
The judgment in IU v BT has practical consequences for courts in EU member states that handle intellectual property disputes with a cross-border element. It confirms that the mere fact that a case is classified overall as a non-contractual matter does not prevent individual issues within that case from being governed by Rome I where those issues are, by their nature, contractual.
This issue-by-issue approach to characterisation is consistent with the objective of the area of freedom, security and justice, which requires predictable and coherent rules for determining applicable law across the member states. Parties to copyright assignment contracts can therefore have greater certainty that questions of formal validity will be assessed under the law designated by Rome I, regardless of the procedural context in which those questions arise.
For assignees of intellectual property rights who bring infringement actions, the judgment underscores the importance of ensuring that the underlying assignment contract satisfies the formal requirements of the law that Rome I would designate as applicable. A defect in formal validity, if successfully raised by a defendant, could undermine the claimant's standing to sue, making the conflict-of-laws analysis a matter of practical as well as theoretical importance.
Conclusion
The Court of Justice's judgment of 24 September 2026 in Case C-176/25, IU v BT, provides authoritative guidance on the interaction between Regulation (EC) No 593/2008 (Rome I) and Regulation (EC) No 864/2007 (Rome II) in the context of copyright infringement litigation. It establishes that a defendant's challenge to the formal validity of an assignment contract, raised as a defence in a non-contractual infringement action, constitutes a contractual matter to be resolved under Rome I, even though the primary claim falls within the scope of Rome II.
This issue-by-issue approach to characterisation reflects the complementary design of the two Rome regulations and supports the broader objectives of judicial cooperation in civil matters within the European Union. Courts and practitioners dealing with cross-border intellectual property disputes should take careful account of this judgment when assessing which law governs each distinct question that arises in such proceedings.
This article is for educational and informational purposes only and does not constitute legal advice.
Sources consulted
Published by Synojus International
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