Pros
Very easy to pass the interview - and this should warn you most. South of France (nice climate).
Cons
Everything else is bad. They promise you interesting and modern project but you'll get technologies from 90's. They promise you french courses but you'll get only imitation of language courses (and don't forget to say "thanks" for them). They promise you some perks (relocation help and canteen compensation) but in fact they are obliged by the French law to provide it, and they do it with a lowest possible price. Low salary and no way to make it bigger. No career opportunities. A very low chance of getting hired directly by contractor company even if you are thinking that you are good developer and you can show yourself - they don't care unless you are graduated from a very expensive french high school. South of France (everything else: very high prices of everything (with low quality), too many tourists). Don't buy tickets for interview by yourself - ask them to do it (because they will have "some problems" to compensate it later if you decline the offer) and don't accept anything less than 39k (of base).