When I checked bitcoin-qt 0.6.0 on Ubuntu 10.04 after switching GNOME 2.30's language settings to fr_CA and fr_BE, I remarked that for some reason the fall-back language wasn't fr_FR but English. So a Belgian French speaker would have to use the application in English. IMHO, for Bitcoin the differences between countries are negligible if not entirely irrelevant so it would make sense to rename French (France) to French only on Transifex. It might also make sense to generally include locales with a country code only if they reach a given percentage of completion, especially if Qt insists on choosing English as the fall-back language rather than the same language with a different country code (right now there's a fr_CA at only 3%...).
Edit: I added French with no country code on Transifex, so feel free to delete French (France).