Frederick heads to the races with Rosanette. She's wearing some new jewelry, which is kind of suspicious, but he doesn't bother pressing her on the issue.
He begins to realize that she isn't all that smart and becomes a little embarrassed to be seen with her in public.
Oh, but he still wants to become her lover. So that's interesting.
A lot of fancy people are there; but most importantly, he thinks he sees Madame Arnoux's carriage.
It's a mix of characters of all classes and moral quality: "Some fashionable ladies left, scandalised by seeing fast women in their immediate vicinity" (1.10.55).
Rosanette wants some attention, too. After all, she's one of the "fast" women and not able to attract attention for her wealth and sophistication. Spotting Madame Arnoux, Rosanette raises her champagne glass and exclaims: Look over there! Look at my protector's wife, one of the virtuous women!" (1.10.63)
Frederick is cringing with embarrassment over her behavior.
To make things worse, they see the Dambreuses. Frederick has been spending a lot of time trying to impress them, and now—to be seen with her! Ack.
They decide to leave the races and go to the Café Anglais, where Hussonet shows up "by surprise" just as he is making a move on her.
A visitor shows up, and she goes to speak to him. Now Frederick is really insulted—all that business and humiliation with Madame Arnoux and being spotted by the Dambreuses with a disreputable lady, and now she leaves him at the table to greet another man! The result? "Now he hated all women; and he felt the tears choking him, for his love had been misunderstood and his desire eluded" (1.11.115).
Cisy and Frederick begin quibbling over social manners and gossip, all to impress Rosanette.
Cisy takes her home, which is a major upset and insult for Frederick. He thought he had the whole thing in the bag.
Hussonet proceeds to tell Frederick about his newspaper, which he has renamed Le Flambard. Frederick couldn't be less interested, and after paying for the entire bill, he leaves—extremely ticked off.
He decides he will play the stock exchange in order to become rich and leave all of his annoying friends behind.