Arnoux stops supporting Rosanette financially and now considers himself her real love. He thinks Frédéric is supporting her and feels as though he’s playing a trick on Frédéric. He asks Frédéric questions about why he never visits Madame Arnoux anymore, and Frédéric lies and says he’s tried but she hasn’t been at home. Arnoux is actually glad Frédéric has stopped visiting.
One night, Arnoux asks Frédéric to fill in for him at the guard post. He returns unexpectedly, having just wanted to spend some time with Rosanette by himself. The men stay at the camp, and Arnoux sleeps with his gun. Frédéric fantasizes about making the gun go off so that Arnoux would die.
The next day, Frédéric meets Dambreuse and Martinon on the street. Dambreuse has just run for election to the Assembly, which angers Frédéric. But Dambreuse claims he had been forced to run. Although he had supported the Republic, he was now starting to try to undermine it. The workers are struggling with poverty, and the government is asking all young men to join the army or go work in the country. Unrest is brewing as workers and the bourgeoisie turn against each other. Dambreuse talks of a new friendship between him and Arnoux. Later, Frédéric gives Rosanette a choice: him or Arnoux. Rosanette says she’s not in love with Arnoux.
Frédéric decides that he and Rosanette should leave Paris, and they go to Fontainebleau. There, they spend a great deal of time walking around the gardens and forests. Immersed in nature, their feelings for each other deepen. He learns about Rosanette’s childhood, and she tells him she tried to kill herself. They move past this and enjoy their time together.
Frédéric learns that Dussardier has been wounded, and he wants to leave immediately for Paris. Rosanette tries to stop him, and he finds her selfish. Once in Paris, it takes Frédéric a long time to reach Dussardier, as he is treated with suspicion. When he finally finds him, Mademoiselle Vatnaz is there, nursing him. Dussardier worries that he is fighting against something that is just. Meanwhile, the fighting in Paris is worsening. Roque arrives to join the fighting, and Louise accompanies him, hoping to see Frédéric. Roque worries himself sick about her.
The Dambreuses invite a large group to their home, including Frédéric, the Arnouxes, Cisy, Martinon, Monsieur Roque, and Louise. Martinon asks Monsieur Dambreuse for permission to marry his niece, Mademoiselle Cecile, although Madame Dambreuse had wanted Cisy to marry her. It is clear that Martinon is Madame Dambreuse’s lover. Louise is happy to see Frédéric, who had been avoiding her. The guests discuss the state of the city and worry about the rebels. They are all happy to be enjoying their luxuries, which they had feared losing after the fall of the monarchy. Frédéric sits next to Madame Arnoux at dinner, but she barely speaks to him. Cisy tries and fails to win back Cecile’s attention. Martinon embarrasses Cisy by bringing up the duel he almost fought with Frédéric, and then Frédéric is embarrassed when Roque begins asking questions about the portrait of Rosanette, which he and Louise had seen at Frédéric’s house when they tried to visit him. Everyone realizes that Rosanette is his lover.