Roger, editor of a women's magazine, meets Roberte, his friend Jean's former mistress, at a major couturier's during a collection presentation. Roberte, who now lives in Florence with her niece Maria, asks Roger to arrange a student exchange so that Maria can come to Paris to perfect her French. Roger approaches Jean's son Philippe, a student at the Beaux-Arts, who agrees to go to Florence. Maria and Philippe meet on the platform at Pisé station. They miss their respective trains and take a walk together. A flirtation begins, then each goes back to the other. Jean finds Maria charming and, like an unrepentant Don Juan, decides to win her over, but thanks to his old maid, his intrigues come to nothing and Maria can marry Philippe.