Hi, welcome to TFO. Maybe one of the other folks referred to this thread will have a specific answer. I don't find myself able to tell based on the image. The tail size and shape look to me to be male, only in that the actual cloaca opening look to be far towards the tail tip. A view with the tail outstretched would help me say more strongly what it looks like.
No need to stress your tortoise for a better picture, knowing the sex, of coarse will not change it. A slightly warm water soak ans they will often stick their penis out. About 36C or 95F is a good temp for this purpose. Then there will be no doubt.
Good to see more people from around the world here on TFO, maybe one of the members who knows these animals well, also writes in French.