I must say I really enjoyed this movie, in many ways. I'll have to include several spoilers to explain how.

First, the story is engaging. Although we know "who did it" almost from the beginning, it makes it even more interesting to follow the investigation.

Even more I enjoyed the actors and their characters. Marina Vlady's is extremely repulsive, but she carries it in such way that you keep wondering: could you resist her charms yourself? Virna Lisi shows another kind of beauty, fragile but just as irresistible. Bourvil's character is actually two persons: until the last half hour he is a Columbo-type investigator, full of self-confidence, playing with the criminal; then he breaks down as he realizes that he is powerless to resolve the case. And Pierre Brasseur is so annoying as the lawyer, omnipotent when in charge of the case, but a toy in his lover's hands.

The ending I like the best, not leaving us with any illusion about the possibility of reaching the justice. Even if the court changes the decision, it will be just a consequence of the lawyer's moves in his immoral game...