I am French and I must say this is the best French film I have seen in quite a while, especially living in the UK.
The humour, jokes and play on words loose some of their meaning in its English subtitles. But I know English people who still very much enjoyed enjoyed it anyway.
I do not recommend the American remake "Just Visiting" which I have seen too, eventhough both Jean Reno and Christian Clavier remain the same characters, it is not a faithful version and is nowhere near as good. Besides, this film is SOOO good, I do not understand why the Americans had to have their own version made.
As for me, I have now watched it well over 50 times (call me sad) but it still gets me in stitches every time. A definit MUST SEE! "C'est dingue, OKAY!"