Hi and welcome to Seibertron!
The only online forum I've found for France is this one: http://transformers.bb-fr.com/
. But that was through Google search, I don't know anything about it.
I don't actually know of any French fans on here (although I'm sure there are), I had never realised until now. In terms of European fans, we have Italian, Dutch, German, Belgian, Spanish, British, Romanian, Serbian, Polish.. and I'm sure I'm missing someone out, I do apologise.
Best of luck with finding fellow Parisians!