The duty to compare language versions of EU law

Résumé

In this article, I examine case law from the European Court of Justice (ECJ) to determine the extent to which natural and legal persons must consult different linguistic versions of EU law in order to ascertain their rights and obligations. Although EU law has equal legal force in all its versions, there are instances in which a linguistic comparison seems necessary. This occurs when a given language version differs from the others. This implies that absolute trust in a single language version read in isolation is not possible, and that a de facto duty to compare linguistic versions exists. This follows implicitly from landmark ECJ judgements, such as CILFIT (1982) and Consorzio (2021). However, in other scenarios relating to linguistic discrepancies, this duty does not seem to exist. When a specific language version is not officially published in the Official Journal of the EU, natural and legal persons are under no obligation to consult other language versions (Skoma-Lux judgment, 2007). Notably, in a recent judgment (On Air Media, 2025), the ECJ ruled on another such scenario. It confirmed that EU legal acts correcting a version of EU law in a specific language have retroactive effect; however, the principles of legal certainty and the protection of legitimate expectations must be respected. Regarding this, the ECJ explicitly ruled out a duty to compare language versions of EU law when the version in question appears clear. This article assesses the various scenarios. It argues that, for the sake of coherence and fairness, there should be no obligation for natural and legal persons to compare language versions. It also suggests that the role of national judges should be enhanced in this regard.