OK, maybe it loses something in translation. My very limited French noticed quite a few occasions where the subtitles where clearly not what was being said, they were just trying, I guess, to make it easier for us foreigners. But it felt a bit of a cheat. I can't believe it made the film better.
Having said that - the film is clearly not a subtle comedy, this is slapstick and farce and, a lot of the time quite visual, and that mostly doesn't need translation - and the film was still a bit crap. Two of the three leads, Jean Reno and Valérie Lemercier braved through there parts well but the story was a time-travel cliche and the humour was mostly tiresome - and the more "comic" characters (particularly those of Christian Clavier and Marie-Anne Chazel) were just unbearable.