The ne bis in idem principle and financial offences

The ne bis in idem principle, which prohibits punishing the same conduct twice, has been the subject of significant developments in financial criminal matters, in particular at the intersection between administrative sanctions imposed by financial regulators and criminal sanctions imposed by the criminal courts.

The foundations of the ne bis in idem principle

The principle is enshrined at Article 4 of Protocol No. 7 to the European Convention on Human Rights and at Article 50 of the Charter of Fundamental Rights of the European Union. It is also recalled by the preliminary article of the Code of Criminal Procedure. It prohibits prosecuting or punishing the same person twice for the same facts, on the basis of identical or similar elements.

Application to financial offences

In financial criminal matters, the principle has gained particular importance after the European Court of Human Rights decisions and those of the Constitutional Council on the cumulative application of administrative sanctions (in particular by the AMF or the ACPR) and criminal sanctions. The Court of Cassation, drawing on this case law, has progressively limited the possibility for the same facts to give rise to both a regulatory sanction and a criminal prosecution.

Recent case law developments

The Criminal Chamber regularly recalls that the cumulative application is only possible if the two procedures pursue complementary aims and protect distinct legal interests, and if they are coordinated in time and in their consequences. Failing this, the criminal procedure may be terminated by reason of the principle. This is a major defence lever in cases of market abuse, insider dealing or breach of regulatory obligations.

Practical implications for the defence

A defence based on ne bis in idem requires a precise mapping of the regulatory and criminal sanctions already imposed or under way, an analysis of the legal interests protected by each procedure, and a strategic timing of the proceedings. The argument can lead to the termination of the criminal action, to a significant reduction of the sentence, or to the dismissal of certain counts. In financial criminal law, this principle has become a structuring element of the defence strategy.