Criminal conspiracy and the non bis in idem principle

The offence of criminal conspiracy, defined at Article 450-1 of the Criminal Code, regularly raises the question of its accumulation with the substantive offences it was intended to prepare, in light of the non bis in idem principle, which the Criminal Chamber of the Court of Cassation has consistently interpreted in a restrictive sense.

The legal definition of criminal conspiracy

Criminal conspiracy is established by any group formed or any agreement entered into for the preparation, characterised by one or more material acts, of one or more crimes or of one or more offences punishable by at least five years' imprisonment. The offence is autonomous: it is constituted by the agreement itself, independently of the actual commission of the offences that were prepared.

The principle of accumulation with substantive offences

The Court of Cassation regularly recalls that criminal conspiracy may be added to the substantive offences prepared, since the legal interests protected are distinct: the agreement to commit offences, on the one hand, and the offences themselves, on the other. This accumulation considerably increases the sentences faced.

The limits set by case law on this accumulation

However, the Criminal Chamber has refined its position to avoid prosecuting the same conduct twice. Where the same material act underlies both the conspiracy charge and the substantive offence, the courts must distinguish the planning conduct from the executory conduct. The defence has every interest in challenging the very characterisation of the conspiracy, by demonstrating the absence of preparatory material acts distinct from the offence itself.

Practical consequences for the defence

The strategy consists, first, of contesting the existence of an organised group or of a prior agreement, and second, of pressing the prosecution to clearly identify the material acts attributable to each charge. This twofold line of attack, combined with a precise analysis of the file, can lead to the dismissal of the conspiracy charge, with significant impact on the sentence imposed.