This is a film I wish Jean-Pierre Melville never made. It's so removed from his milieu that I can't help being reminded of Alfred Hitchcock's involvement with the romantic comedy, MR AND MRS SMITH. It seems, however, that Melville wanted to do it so he has only himself to blame.
Here we are treated to a couple of overbearing teenagers orphaned early in the story -- apparently without emotional effect. Their story in the first part of the film is mostly confined to their shared bedroom in which torment each other at the top of their lungs. Some people are fascinated by this psychopathology, but it was pure hell for me.
Nicole Stéphane as the sister has been revered for her performance -- yet I found it constantly over-the-top. I tolerated the performance of the actor playing the brother, Edouard Dermithe, better -- while he was roundly jeered by the critics. Because I don't speak French, I am reacting to only part of his performance.
An hour into the movie, and 46 minutes before the end, the film finally opens up and shows some momentum. That's about the time the American appears. He sings a pleasant ballad with a pleasant-enuf voice. Then the film begins to descend again, but it ends before it sinks to previous depths.
Jean Cocteau's source novel is considered a classic. Many people rank this film as a classic. That may be all you need to know about it.
If, like me, you want to see everything Melville did, than you have already decided to see this film. Just be aware that it is nothing like Melville's others ... I'm happy to say.