From what I heard French are obliged to surrender encryption keys at the request of authorities or go to jail for a few years for denying their request. The only thing that may be left is to pack your things and go.
You don't have to surrender the key, but you are required to at least decrypt things for the authorities.
However, I the twist seems to be in the word "susceptible": any encryption key is susceptible to be somehow used to commit a crime, while on the other hand a jury would probably "deny a request" of the authorities if they can't show enough evidences.