IECL Lunchtime Seminar with Laurence Usunier – Can the Forum Court Review the Constitutionality and Conformity with International Conventions of Foreign Law?

The IECL Lunchtime Seminar Series offers our Academic Visitors an opportunity to share their research, exchange ideas, and connect with colleagues on both substantive and methodological aspects of their work.

Each seminar usually lasts 30–45 minutes, with 20–30 minutes for the presentation followed by 10–15 minutes for Q&A. A light sandwich lunch will be provided.

Prof Laurence Usunier
Can the Forum Court Review the Constitutionality and Conformity with International Conventions of Foreign
Law?

Abstract: Laurence Usunier will present her current research project, which focusses on the interaction between private international law and sources of law. Professor Usunier will teach a course on this topic at The Hague Academy of International Law in July 2026. The course title will be, more specifically: Private International Law Faced with Changes in the Sources of Law (to be published in the Hague Academy Collected Courses series). Its purpose is to investigate the interplay between private international law and sources of law in general, while looking more specifically at the transformations that have affected the sources of law in recent decades and their possible impact on the resolution of private international law problems.

While issues of sources are central to all branches of law, they take on additional importance and dimensions in the field of the conflict of laws. The first and most obvious question they raise is that of the sources of private international law itself. The specificity of the discipline from this point of view is that it has been largely unified through international conventions and, in Europe, through EU regulations. These long-standing and extensive efforts to harmonise private international law have turned the discipline into a tremendous laboratory for the internationalisation and Europeanisation that now affect virtually all branches of private law. In this respect, private international law provides a particularly rich framework for analysing the pros and cons of the internationalisation and Europeanization of private law, as well as for identifying the ways to articulate harmoniously the intertwined sources of private law and resolve conflicts that may arise between them.

In so far as the goal of private international law is to identify the legal rules that shall govern private law situations having connections with more than one jurisdiction, it is important to consider, not only the sources of private international law itself, but also the sources of the substantive legal rules that private international law renders applicable to private law relationships. This second aspect of the interplay between private international law and sources of law raises many questions in itself. The seminar will focus on one of these many issues, which relates to the growing Europeanization, internationalisation and “constitutionalisation” of private law. Given the increasing number of states allowing their courts to set aside statutory legislation that is contrary to an international convention or to the Constitution, the question arises as to whether the forum court—that is, the court before which a case is pending—may review the compatibility of the foreign law governing the dispute with the Constitution of the foreign state, with international conventions ratified by this state, as well as with EU law when the applicable foreign law is that of an EU member state. For example, would it be possible for a US court having to decide a dispute governed by French law to set aside an applicable French statutory provision that seems to violate the French Constitution, the European Convention on Human Rights, or EU law? The speaker will seek to explore possible answers to this question.

***

Laurence Usunier is Professor of International and Comparative Law at the Sorbonne Law School (Paris 1 Panthéon-Sorbonne University). She holds an LLM and an LLD in comparative private international law from Paris 1 University. Her fields of expertise are the conflict of laws, comparative law, sources of law and consumer protection.