If that freewheel does not work out for you, let me know. I have a Heavy Duty freewheel setup from the old Sick Bike Parts stock that I would be willing to part with. The shipping from where I live in the U.S. to France would likely be very expensive, but this freewheel and it's bearing are designed to work with motors and are built stronger than the freewheels found in most of the cheap kits. It would just depend on how much you need it.
Of course, my Grandmother would haunt my soul forever if I didn't get one word in French-wise.
Je vous souhaite bonne chance dans les épreuves à venir.