this is a remake of "L'homme de Rio" of the same director and also starring Belmondo. The producers told De Broca to make a "super"-L'homme de Rio this time. But the comedy is taken a bit too far this time, which means the border to pure slapstick is crossed several times throughout the movie, which is unfortunate. Also the actor of the suicidal millionaire and the actor playing his butler should have switched roles; I think even the director stated that once in an interview.
There are several references to its preceding movie, most obvious; in one scene the girl calls Belmondo "Arthur" instead of "Adrien"; "Arthur" was the name of Belmondos character in the first movie. In the first movie Belmondo asks his girl; "what's next, are we going to China?".
User reviews of "L'homme de Rio" correctly mention the fact that Spielberg very obviously was inspired by that '63 French movie when making Indiana Jones. Well, watch this movie and you will experience even more deja-vus.
This is a well done and very entertaining adventure-comedy movie. Go see it.