Immunity and Sincere Cooperation: When the eppo Challenges the Court of Auditors

This editorial examines the institutional conflict arising from the action brought by the European Public Prosecutor’s Office (EPPO) against the European Court of Auditors (ECA) before the Court of Justice of the European Union, concerning the refusal to lift immunity and confidentiality obligations of ECA officials called to testify as witnesses in a criminal investigation. The case raises fundamental questions about the scope and function of immunities and privileges under EU law, the principle of sincere cooperation enshrined in Article 13(2) TEU, and the balance between effective criminal investigations and the protection of institutional independence. By analysing the legal arguments advanced by the EPPO, relevant ECJ case law on immunity, and the interplay between immunity and the right to silence, the editorial highlights the novelty and sensitivity of this dispute. It argues that neither a strictly hierarchical nor a purely horizontal model of interinstitutional relations is adequate. Instead, the case points towards a form of regulated cooperation under judicial supervision, in which the Court of Justice is called upon to clarify the limits of immunity, prevent its defensive misuse, and address unresolved issues concerning procedural safeguards in EU criminal proceedings.