A good source of high quality good value chromoly axles in the UK is weldtite but I don't know their availability in France. I'm sure there is a similar company over there. You'll need to measure your existing axle.

Bike Bits | Weldtite

Over here the difference between a high quality and lower quality axle can be as little as a pound.

There are uk companies that I think have free postage to France over a certain value which isn't too high if you are struggling to source in France. Some of the specialist bmx bike shops have the best axles though.