This is an excellent film to watch provided you are able to suspend disbelief and just accept the movie for what it is. Otherwise, you will probably sit there and repeatedly say to yourself "this couldn't possibly have happened".
The film begins after quite a bit of back story has already taken place. What had happened up to the beginning was that Jean-Paul Belmondo is a French agent who was sent to Madagascar to kill the dictator. However, in a twist, the French government has changed their mind about the assassination AND decided to inform the King that Belmondo is coming to kill him. You never know why there is a change of heart AND betrayal of Belmondo. The film begins with him on trial for the plan and Belmondo won't betray his government--even though this is exactly what they'd done to him.
After two years in hard labor, Belmondo and another prisoner escape and eventually he makes his way to Paris. Now, angry and wanting retribution, he lets his old bosses know that he STILL intends to kill the King and will do so during his state visit to France. Why they didn't just cancel the King's visit, I have no idea. Instead, they try to both protect him and capture Belmondo. The problem, however, is that the French secret service is apparently manned by morons, as again and again, he is able to slip past them--in sort of a game of cat and mouse. At first, I thought this was kind of clever, but after a while it just seemed a bit...annoying. After all, no enemy is THAT stupid--and the police and secret service can't be that dumb, as Belmondo was one of them originally! In several cases, dozens or even hundreds of men surround a location--only to have Belmondo just sneak right in like it's no big deal! This is a severe handicap of the film--making him defeat and out-think the police could have been more interesting if the police hadn't been like the Keystone Kops.
However, despite this major complaint, there is a lot to like. Jean-Paul Belmondo is great. He does many of his own stunts and his athleticism was amazing. I especially loved his ability to take a fall or do acrobatics, but his style and acting also carried the film. I also loved the car chase--it was even better than such great chases as in DIVA and LA BALANCE--two other wonderful French films. Additionally, how the assassination went down at the end of the film was brilliant--once you got past the silliness of how he just slipped into the compound! Also, while many will no doubt dislike the downbeat ending, I thought is was excellent.
Overall, interesting and entertaining brain candy. With a smarter enemy, this film could have been fantastic.
By the way, a review that was written some time ago complained that the film was dubbed. The DVD I saw was, thankfully, captioned--not dubbed! Hurray!