The current Dominion French Editor (Ystari) just said a few days ago he wont publish Empires in French (at the end of this thread http://www.ystari.com/cherchez-une-aventure-en-boutique/).
Is someone here who know if there will be another french editor to publish it or May I have to buy an english edition of Empires ?
If the French publisher doesn't want to publish it, I doubt that some other French publisher will be recruited. If that were possible it would be pretty unfriendly to the current French publisher; probably it would just need to be that RGG switched French publishers.
The problem with Empires is the metal tokens. They're expensive. Several publishers decided against doing Empires because of how expensive the tokens were. We have offered them chits to use instead. The problem is that then you look so cheap, having chits instead of the pretty tokens. I believe a few publishers will use the chits though, rather than skip the expansion.
IIRC only Germany will have the metal tokens, while Japan and the Dutch will have the chits. But I won't know for sure that any particular language will have it until someone reports getting it.