The ne bis in idem principle in the European Union legal order: between scope and substance

Abstract

The contribution focuses on the relationship between the substantive interpretation of the ne bis in idem principle in the case law of the European Court of Justice in competition matters in particular and the scope of application of the principle in the light of Article 51 of the Charter of Fundamental Rights of the European Union. In its case law on Article 54 of the Convention on the Implementation of the Schengen Agreement the European Court of Justice emphasises the wording and function of the principle in the context of enhanced cooperation whilst in competition matters, the Courts’ interpretation of the ne bis in idem principle derives from the contours of the enforcement landscape. By contrast, the European Court of Human Rights precisely emphasises the uniform and coherent development of the ne bis in idem principle in its case law, revealing differences in the attitudes taken by the two European courts to the realisation of the ne bis in idem principle on the European level. Now that the Charter is legally binding, the scope and substance of the ne bis in idem principle must be considered in the light of Articles 50, 51, and 52 of the Charter. When read in the light of Article 51 of the Charter, the requirement of the ‘unity of the protected legal interest’ in the case law concerning the ne bis in idem principle in competition matters implies that the member states are bound by the ne bis in idem principle in European Union law when they are “implementing European Union law” within the meaning of that provision.