Act 1
The action opens in Magda’s salon in Paris at twilight. Magda is with her patron Rambaldo and a group of friends. The poet Prunier amuses Yvette, Bianca and Suzy by declaring that romantic love has become fashionable in Parisian high society, especially among women. At the piano, he performs a new song he has composed about Doretta, a young woman who rejects a king’s advances in favour of true love; Magda completes the song for the admiring crowd (‘Chi il bel sogno di Doretta’). Rambaldo is cynical but he gives Magda a necklace; Prunier observes that Doretta would not be so susceptible to money. The maid Lisette rushes in, informing them that a visitor is waiting; he is the son of an old friend of Rambaldo. The men and Lisette depart, and Yvette, Bianca and Suzy reflect that Magda is privileged with Rambaldo. Magda, however, thinks nostalgically of when she was a young grisette; she recalls an evening she ran away from her aunt to go to Bullier with a young man (‘Ore dolci e divine’). Prunier returns and remarks that his own preference is for artistic, decadent women. Rambaldo introduces Ruggero, who has just arrived in Paris. Prunier reads Magda’s palm and predicts that she will migrate like a swallow, but to an unknown fate. Prunier declares that Paris is overrated but Lisette interrupts him and praises the city; the women recommend Bullier for Ruggero’s first evening. Everyone leaves the salon except Magda, who reflects on Prunier’s premonition. After she leaves, Prunier and Lisette enter; they are secretly lovers and he chooses her clothes, which she has taken on the sly from Magda (‘T’amo! Menti!’). After they leave, Magda returns dressed as a grisette, remembering Prunier’s story about Doretta.
Act 2
The action moves to Bullier’s. A huge crowd of students, artists, grisettes, flower sellers, waiters and customers move around the hall, which has a grand staircase to the left, a garden at the back and a balcony. Members of the crowd flirt with one another, and demand drinks; Ruggero sits shyly in a corner, where he is approached by Georgette, Gabriella, Lolette and other grisettes. Magda arrives and attracts the interest of a group of students; she pretends she has a meeting to move away from them, and approaches Ruggero. He asks her to keep him company and tells her she reminds him of the modest girls in Montauban. They dance together and become lost in the crowd (‘Nella dolce carezza della danza’). Prunier and Lisette arrive; he is praised by the crowd as the poet of love, and Georgette, Gabriella and Lolette pursue him (‘Deh! scendi dall’Olimpo!’). Magda and Ruggero order drinks, reviving Magda’s memories of her youth; she toasts to his loves but Ruggero sharply declares that if he loved, it would be only once and forever. They embrace (‘Perché mai cercare di sapere’) but are interrupted by Lisette and Prunier. The poet and Magda recognise one another but stay quiet; Lisette is convinced ‘Paulette’ is really Magda but the idea is mocked, and Lisette confesses she has borrowed her mistress’s clothes. The four lovers toast to love, supported by the crowd who throw flowers at them (‘Bevo al tuo fresco sorriso’). Suddenly, Prunier sees Rambaldo arrive. As the crowd begin to leave, Ruggero takes Lisette away and Rambaldo approaches Prunier and Magda; the poet tries to hide Magda. Rambaldo asks Magda to leave with him but she refuses, saying she loves the young man; Rambaldo says love is an old wives’ tale, but he leaves Magda to make her choice. As dawn breaks, an offstage voice sings that morning dispels the illusions of the evening, and that love should not be trusted. Ruggero and Magda embrace (‘Paulette! Mia Paulette!’); she is drained and fearful as her romantic dream is realised, but she clings to Ruggero as her energy seems to return.
Act 3
Three months later. The action takes place on the pavilion of a grand hotel in the Côte d’Azur, in the late afternoon. Magda pours tea and she and Ruggero embrace one another, reflecting on their happiness in this new life. Suddenly they are interrupted by Fleury, Mariette and Rorò, fashionable saleswomen who present the latest clothes. Magda and Ruggero tell them they are too poor and the women leave laughing. Ruggero consoles Magda and tells her their financial struggles will soon be over: he has asked his family for permission to marry Magda (‘Dimmi che vuoi seguirmi alla mia casa’). She is shocked, but he reminds her that love is forever and he wishes to bring her home and raise a family. Ruggero leaves and Magda is tormented by his ignorance of her past. She enters the pavilion and Lisette and Prunier arrive, arguing: Prunier tried to launch a singing career for Lisette in Nice but the public mocked her. The butler greets them and announces their arrival. Magda is surprised; she tells Prunier she is completely happy but he responds that she is not suited to this modest life. Lisette offers to return as Magda’s maid and Prunier adds that Magda will also return to her old ways; Rambaldo has asked him to deliver this message. Lisette and Prunier leave together, now reconciled, and Rambaldo arrives (‘Che volete da me?’). He tells Magda that the swallow will eventually return to its nest and he leaves a small wallet, asking for Magda’s forgiveness. Ruggero appears, in distress and holding a letter; Rambaldo exits quickly. Magda reads the letter revealing the truth about her past in Paris; Ruggero violently accuses her of betrayal. He sees the wallet on the table and the couple fight over it; Ruggero throws the money in Magda’s face and pushes her to the ground. She pleads for his forgiveness, crawling on the floor (‘Non maledire, ascolta’); but he curses her and leaves forever. Lisette arrives and comforts the heartbroken Magda. The two women walk off into the distance together as the evening bells toll.