A cat burglar joins the circus to escape the police, and allows the ringmaster to surgically implant him with wings. He continues his thefts during his off-hours, but gets involved in the problems of people around him, while also romancing one of the other circus performers.

Michel Piccoli stars as an amorous dentist whose philandering seemingly knows no bounds. He is no sooner shooing such lovelies as Anna Karina and Elsa Martinelli out the back door than he is welcoming such "new blood" as Joanna Shimkus into his living room. When Shimkus demands a commitment, Piccoli runs home movies of his past girlfriends, insisting all the while that he has forgotten them and that Joanna is the only woman in his life. The very next day he's running his movies for still another woman, and the song continues. De L'Amour is based on an 1822 novel by Stendhal (who would have been visionary indeed if he'd included all those home movies!)

In the aftermath of war, two men and a woman begin acting more like children than adults, leading to tragedy.