Subreddits have a "language" setting, although the data is probably dirty since the value is unused AFAIK - for all we know /r/pics is currently set on "Klingon". The Reddit admins would probably have to do some manual dirty-work, but iirc the "default subs/front page" reddit listing is somewhat manually curated anyways.
either way, if you stick to the idea of an entirely french version, fr.reddit.com/r/football will lead you to the american football subreddit, but for a french guy they would expect soccer to be there...
It's still gread that they provided a multilingual UI, but as a whole, us companies could always use to understand the foreign market a little bit better than just providing a UI translation...
That said, http://fr.reddit.com/ should be the top posts from the French-language subreddits, not just the main frontpage with a French UI.