Philippe de Morannes has an agreement with his girlfriend, the well-known actress Paulette Nanteuil. Either one of them can sleep with someone else if they give their partner a day's notice. In the six years they have been living together, this agreement has not been an issue. Philippe is researching a book about Carl Herickson, an international screen star. One day, while waiting in the star's suite for him to return, he encoutners Claudine, a friend of Paulette's who is a journalist doing an interview of the star. In the midst of a mild but very witty flirtation with her, the star arrives, and expresses a wish to see a local theatrical performance. Hardly thinking about it, he recommends his wife's current play. In a series of misadventures, the film star and the stage star wind up sleeping together. The next day, Philippe and Paulette have a heated and funny discussion about who was unfaithful to whom. This comedy is a remake of the 1938 film Quadrille, by Sacha Guitry.