Les Belles Manières on AllMovie

Camille (Emmanual Lemoine) is a young provincial man who comes to Paris in response to a newspaper ad. He takes a job in the household of Helene Courtray (Helen Surgere), bringing meals to her son, who has become a complete hermit. As he grows more familiar with Paris, he discovers something of its nightlife. At that time, he discovers that his long-lost sister has become a prostitute. Mrs. Courtray leaves him alone with her son in the house for a few weeks, and on the day of her return, Camille simultaneously buys flowers for the apartment, and then sets it on fire. Despite Mrs. Courtray's wish to help him, Camille is more troubled than she suspects.