When Same-Sex Marriage Crosses Borders

The CJEU’s judgment in Jakub Cupriak-Trojan and Mateusz Trojan v Wojewoda Mazowiecki (better known as Cupriak-Trojan) is one of those rare decisions that is not only welcomed as a rights judgment, but also structurally important for private international law. The case concerned two same sex Polish nationals, one also holding German nationality, who married in Berlin in 2018 and then asked for their German marriage certificate to be transcribed into the Polish civil register when they wanted to live in Poland as a married couple. Polish authorities refused because Polish law does not permit same-sex marriage. In its 25 November 2025 judgment, the Court held that Articles 20 and 21 TFEU, read with Articles 7 and 21 of the Charter, preclude a Member State from refusing recognition and transcription where that is the only available way to give effect to the marriage status lawfully acquired in another Member State.

That is the heart of the matter, and it deserves to be celebrated. The Court is not asking Poland, or any other Member State, to introduce same-sex marriage into its domestic family law. What it is doing is more subtle and, for private international law, more consequential: it is refusing to allow a lawfully acquired family status to become invisible at the border of the home Member State.

Beyond the Recognition Debate, Towards Continuity

Several early commentaries have already begun unpacking the implications of the CJEU’s decision in Cupriak-Trojan, particularly focusing on the implications of cross-border recognition of same-sex marriage within the Union. For instance, discussion on the European Association of Private International Law blog has focused on whether the judgment’s logic ultimately requires full recognition of marital status across Member States, rather than the fragmented recognition of only certain legal consequences. Much of the emerging academic commentary similarly situated the judgment within the trajectory opened by Coman and Others v General Inspectorate for Immigration, examining how the Court balances Member State autonomy in family law with the demands of EU free movement, mutual trust, and non-discrimination. Building on that discussion, the present analysis focuses more specifically on how the logic of cross-border status recognition may operate across multiple areas of EU private international law. If a marriage validly concluded in one Member State must continue to produce legal meaning across the Union, the implications inevitably extend beyond civil registration alone. Questions concerning matrimonial property, succession, parental status, adoption, pension entitlements, and administrative recognition quickly follow. In that sense, the significance of Cupriak-Trojan may lie not only in its immediate recognition, but also in the broader challenge of ensuring that the legal effects attached to family status remain coherent across different areas of EU law. The judgment therefore exposes unresolved questions about how existing EU private international law mechanisms will operationalise status recognition in practice.

Unlike Coman and Others v General Inspectorate for Immigration, which recognised same-sex spouses for residence rights under free movement, Cupriak-Trojan raises the broader issue of whether a marriage validly concluded in one Member State can be denied civil status in another. Courts and legislations have previously stated that, in effect, member states need not “recognise the marriage” so long as they recognise some of a marriage’s legal consequences. Cupriak-Trojan makes that distinction harder to sustain in a Union built on free movement, mutual trust, and fundamental rights. The earlier Opinion of the Advocate General, as summarised in the AG’s press release, points to concrete everyday consequences of non-recognition, including property, taxation, inheritance, and the capacity to continue family life without legal fragmentation. That is exactly the kind of “limping status” private international law is supposed to prevent, not normalise.

This is also where the human-rights dimension becomes indispensable. Article 7 of the Charter protects private and family life, while Article 21 prohibits discrimination on grounds including sexual orientation. The CJEU’s approach sits comfortably within a line of Strasbourg authority that has steadily pushed states toward legal recognition and protection for same-sex couples. In Oliari and Others v Italy, the ECtHR held that the absence of a legal framework recognising same-sex relationships violated Article 8. In Orlandi and Others v Italy, the Court dealt specifically with refusal to register foreign same-sex marriages. In  Fedotova and Others v Russia, the Grand Chamber held that complete non-recognition of same-sex couples was incompatible with Article 8. The AG in Cupriak-Trojan expressly drew on the Strasbourg trajectory, including Przybyszewska and Others v Poland, in which the ECtHR found that Poland had failed to put in place a specific legal framework for same-sex unions.

Indeed, the implications of the judgment may extend even further than evidentiary recognition alone. Following the CJEU’s ruling, the Polish Supreme Administrative Court ordered the transcription of the marriage into the Polish civil registry. Such transcription carries significance beyond mere administrative acknowledgment. Once transcribed, the spouses may request a Polish marriage certificate capable of producing legal effects within the domestic legal order, suggesting that recognition may operate not merely evidentially but also constitutively. This development reinforces the possibility that the logic of Cupriak-Trojan may ultimately require a more robust form of status recognition than some Member States may initially have anticipated.

The Private International Law Spillover

What makes the judgment especially interesting for private international law is not just what it resolves, but what it leaves open. If the civil register must be opened to foreign marriages, what about other status-adjacent consequences that depend on proof of marital status? What happens once that status begins interacting with adjacent legal and administrative regimes? The AG explicitly recognised the need for procedures that prevent same-sex couples from falling into a legal vacuum on matters such as property, taxation, and inheritance. The Court’s judgment gives that logical judicial force; the next challenge for Member States and EU institutions is ensuring that such recognition functions coherently across different legal and administrative contexts.

That is why this case should be read as a private international law judgment with broad systemic consequences, as a structurally important private international law judgment. Mutual recognition has long been one of the Union’s most powerful legal techniques, but it usually operates through sector-specific instruments such as the Brussels I Regulation for civil and commercial judgements, the Brussels IIb Regulation for Divorce and Parental Responsibility, and the EU Succession Regulations for Succession law and technical connecting factors. These regulations precisely exist so that recognition remains consistent across the EU and borders are not a hindrance. While both the Strasbourg and Luxembourg jurisprudence increasingly point toward recognition of the marriage status itself, rather than fragmented recognition limited to specific legal consequences, important practical questions remain regarding how that status is to operate across different legal and administrative contexts. Without clearer coordination, there remains a risk that different authorities may attach different consequences to the same marital relationship, producing uneven recognition across legal contexts.

From Recognition to Coordination

The next challenge, therefore, is no longer recognition itself but managing its spillover effects within EU private international law. One sensible way forward would therefore be a dedicated EU civil-status recognition framework for marriages lawfully concluded in another Member State. Such an instrument would not require Member States to introduce same-sex marriage domestically but could instead focus on ensuring that marital status validly created in one Member State remains legally meaningful across the Union. In practical terms, it could establish a standardised and non-discriminatory procedure for recognition and transcription of foreign marriage certificates, clarify the legal consequences of recognition across core private-law fields such as succession, matrimonial property, and family reunification, as well as include explicit safeguards for parental status and the best interests of the child, so that children are not exposed to fragmented recognition when their parents’ marital status crosses borders.

In some respects, developments in this direction are already visible at the Union level. The Proposal for an EU Regulation on Filiation similarly seeks to address the cross-border recognition of parental relationships within the Union, particularly in situations where the status of a child or parent legally established in one Member State risks losing recognition in another. Although the Proposal focuses specifically on filiation, it reflects a broader concern within EU private international law with ensuring continuity of personal and family status across borders. Whether the instrument is ultimately adopted, and in what form, remains to be seen, but it nevertheless illustrates the growing recognition within the Union that fragmented status recognition can undermine both legal certainty and free movement. At the same time, more immediate steps may also be possible. As the Advocate General already observed, Member States require “appropriate procedures” to make such marriages public with respect to third parties and to avoid legal vacuums. In that sense, Commission guidance or a Council-led political declaration could serve as an interim measure, helping national authorities coordinate administrative practice and reduce uncertainty while a more comprehensive legislative solution is developed. Such regional coordination would simply reflect the Union’s existing commitment to free movement, legal certainty, and the continuity of family life across borders.

Indeed, such forms of soft coordination may in some respects prove more effective, at least in the immediate term, than attempting to introduce a comprehensive legislative instrument. The experience of differentiated integration within EU private international law, including under instruments such as the Rome III Regulation, demonstrates that fragmented participation can itself generate new asymmetries across the Union. A future Regulation on civil-status recognition could therefore risk entrenching opt-outs or creating the misleading impression that obligations of recognition arise only for participating Member States. Yet the logic of Cupriak-Trojan suggests that obligations of recognition already flow directly from EU law itself. In that sense, the more immediate challenge may not be the creation of entirely new obligations but clarifying the scope and practical implications of obligations that already exist within the Union legal order.

Seen in that light, Cupriak-Trojan is a success story for both equality and legal coherence. It protects the dignity of same-sex couples who have already lawfully built a family life within the Union, and it pushes EU private international law toward a more honest account of civil status portability. The judgment’s real legacy will depend on whether the Union is willing to follow through: not by relitigating the right to recognition, but by building the procedural and substantive architecture that recognition now requires.