7 years ago, Jean and Anne-Marie were sweethearts, but Jean was arrested for stealing and jailed for 5 years. Marianne thinks that Jean is coming to see her, so she sneaks out and goes with him for a walk, remembering their happy times together. They arrive at Impasse des Deux Anges, where they were most happy, but now the place is a ruin (and a dead end) - perhaps like their relationship now. 7 years is a long time and all this time Marianne doesn't know that her Jean is a thief. Now he is even a better thief. The abyss between them is now too wide, and when Marianne has to choose between Jean and Antoine, it's not a difficult matter.
Jean himself becomes a different man after meeting Marianne. He is supposed to hand the necklace to his friends who are waiting at the gate, but he doesn't give it to them and all night crooks are following them both. After spending the night with Marianne, Jean realizes how he has been wrong. Anne-Marie loved good things, but if Jean had to steal to get them, she preferred not to have them, as to be with Jean was more precious.
The movie is beautiful and poetic although I felt it was slow at some parts (perhaps because I wanted to do something else): i.e. the scene with a poor young girl, also called Anne-Marie, where Marianne tries to tell her that once she was poor also; and the scene with a man who takes Jean's gun and threatens them.