Irma La Douce is a successful prostitute, living in Paris. A poor law student, Nestor le Fripé, falls in love with her and is jealous of her clients. In order to keep her for himself, he assumes the disguise of a rich older man, "Oscar", and takes many jobs. Finally no longer able to sustain his exhausting life, he "kills" Oscar, is convicted of murder, and is transported to the Devil's Island penal colony. He escapes and returns to Paris, and proves that he is innocent. He and Irma reunite.
Musical with music by Marguerite Monnot and French lyrics and book by Alexandre Breffort.