Act I. Paris
The courtesan Magda and her protector Rambaldo the banker are hosting a party in their splendid parlour in Paris. The poet Prunier is entertaining guests with a small talk. The maid Lisette announces a visitor to RImbaldo: a son of his old friend has just arrived in Paris from the country. The banker leaves, and after some time returns with a young back-countryman named Ruggero. The naive young man, so different from the cohorts Magda is used to, makes her fall in love with him at first sight. Prunier notices her confusion. To divert her he reads her palm and foretells one day she will fly for her love and happiness like a swallow.
Act II. Bullier's
Artists, students and flower girls are talking, singing and dancing merrily. Magda arrives. Answering to the jokes and provocations of drunk young men she sits herself down at Ruggero’s table as if by mistake, and introduces herself as Paulette. Not recognizing the hostess of the parlour, Ruggero loses his head over her charm and beauty. Prunier and Lisetta come, then Rambaldo. Prunier and Lisetta try to prevent the banker from seeing Magda, but he notices her and demands an explaination. Magda tells Rambaldo that she has met her true love and has to leave him.
Act III. The French Riviera
Magda and Ruggero have been living in Nice for several months. Despite problems with money they are happy on their Mediterranean villa. Ruggero writes a letter to his mother asking for her consent to his marriage to Paulette. He shares with Magda his dreams of their idyllic life together in the countryside. Magda in torn between the desire to confess everything to Ruggero and the fear of losing his love. In her reply Ruggero’s mother gives him his blessing if his fiancée is pure and innocent. Disconsolate Magda tells Ruggero that she can never be his wife. In spite of his pleas and tears Magda leave Nice with Lisette.