I was convinced that the burden of proof must still rest with the prosecution, and that the accused is innocent until proven guilty under Code Napoléon. This makes me sure about that conviction
Déclaration des droits de l’Homme et du citoyen
26 août 1789
...
Article 9 - Tout homme étant présumé innocent jusqu’à ce qu’il ait été déclaré coupable, s’il est jugé indispensable de l’arrêter, toute rigueur qui ne serait pas nécessaire pour s’assurer de sa personne doit être sévèrement réprimée par la loi.
However, there seems to be a myth that one is presumed guily, and the burden of proof is with the defence. i don’t where this myth comes from, but it may have something to do with the role of the investigating magistrate (juge d’instruction). This can sound like the judiciary is batting for the prosecution, but in fact the investigating magistrate is responsible for determining the facts of the case before it comes to trial rather than refereeing adversarial proceedings, which is always handed to a different judge. In fact, I don’t think you can enter a plea in civil law cases - if you say you’re guilty, the investigating magistrate takes your confession as evidence rather than a plea.
Here’s a decent article on the inquisitorial system.