Have you tried networking using LinkedIn or similar? Maybe that could be a way to get to know developers and designers.
It is hard to find anything like SitePoint. There are few that are better, of course (in English) but most are of less quality.
I guess that it is also because English is a much international language. There a few ones in Spanish but I guess that's because of the number of countries that use that language.
If there's nothing of high quality in French, you may even want to considere if there's a real need for this type of forum and create one yourself.