Les Amants (The Lovers) (1958)
Director: Louis Malle
Les Amants caused a bit of controversy when it was screened in America in the late 1950s; according to Wikipedia, it was the 'allegedly obscene material' the film contained, ie. sex scenes. While these sex scenes are no longer shocking (though quite romantic in their lovely black-and-white cinematography), I can see why they shocked censors in the 1950s. Not only are the couple having sex (and a lot of it), but are committing adultery at the same time.
The plot of the film is what I would call 'very French.' A young married woman, Jeanne, is having an affair with a man in Paris, and is feeling highly unsatisfied with the whole situation: neither her husband or her lover inspire get passion in her. After several moves to change the situation, she ends up in the arms of yet another man, a second lover who she falls in love with during one night of love-making.
The plot isn't a great one, and none of the characters are really that likeable. However, they and the film look beautiful. Jeanne Moreau (Catherine from Jules et Jim) does play Jeanne well, and I liked her a bit better after she had a laughing fit half-way through the film.
The film is fine, neither great nor terrible. I did like it more than Jules et Jim but it has less importance for film history than Truffaut's film. I don't know if I would recommend it, but also cannot say anything really negative about it either. If my description has piqued your interest, you should see it; if not, then you needn't bother.