Robert Lafleur (Scaramouche) is an actor in 18th century France who spends most of his time, including when he should be on stage, light-heartedly having love affairs and generally enjoying life. One day, a marquis visits him and asks him questions about the birth mark on his shoulder...

Lydia (Danielle Darrieux) is a student, poor and orphaned, who pretends to be the daughter of a famous writer.