The whimsical Jean Latour wins a competition for a month's holiday on the Côte d'Azur. When he arrives at the "Villa Sans Souci", he discovers that the owner and generous donor, M. Mallez, is a doctor, that the property's guests are sick with nerves, and that Mallez has brought him in to entertain his neurasthenic residents.
Peter is a talented young composer who has so far not been able to get his revue “Traumschöne Nacht” in a music theatre. Behind the scenes of the “Alhambra”, a Paris music hall, he meets Violetta, a young up-and-coming artist. For her sake, Mr. Maroni, the director of the “Alhambra”, who is in love with Violetta but is rejected by her, has organized a costume party at which the young entertainer appears as a little flower seller. When Peter shows up there too, he believes that Violette is actually selling flowers.
The maid of a clandestine brothel in Marseille is found murdered. The inspector Sergil, in charge of the investigation will employ somewhat particular methods in order to unmask the assassin.
Pierre Chambrac, a French industrialist, and Canadian Paul Laforêt, two former brothers in arms, meet again by chance in Paris five years after the end of World War II. Pierre is engaged to a beautiful foreign young lady by the name of Helen Bering. He introduces her to his friend, which seems to trouble him. To his amazement, Helen and Paul disappear without notice. Pierre, who was beginning to feel jealous, sees his suspicion confirmed. He decides to fly to Montreal where he thinks the couple has taken refuge. Once there, he learns that his dear Helen is actually a criminal and that Paul is a policeman whose duty was to arrest her.