Are French users your main or only user base? (I just fiddled around to find the language setting to set the forum UI to English, but well… the content is French of course anyway.)
If so, maybe it would help to make that forum multi-lingual or at least have an English-speaking category as well… many people speak English and for FLOSS projects it is quite a default.
I mean your repo and I guess source code is also in English.