And if you're required to supply some documentation from another country, you're likely to be required to get it translated to French by an official translator (which not only takes time but can be quite expensive). In contrast, I've never had a problem handing in German documents to authorities in Sweden and Swedish documents to authorities in Austria. Documents in English have certainly been accepted everywhere outside of France.
The catch-22s are the best. Renting an apartment requires that you have a French bank account, and getting a French bank account requires that you already have somewhere to live in France...