Death Threat(1950)

Original title: Menace de mort

André Garnier, a young pianist, who was sent to deportation following a denunciation, absolutely wants to find his informer. He falls in love with Hélène, the mistress of a wealthy industrialist, Bernier, in whom he soon discovers the man who once sold him to the Gestapo. Bernier is soon found murdered. André deflects suspicion on Jacques, the victim's secretary. Hélène and André's affair ends up being discovered by the police, who seem to see in it the motive for the crime. André surrenders to justice.