What lessons must Florent learn in this "new" Paris?

Florent learns to adjust to a world that has gone on without him. Florent's tenderheartedness and his unrealistic idealism lead him to put his trust in untrustworthy people. In addition, Florent learns some very hard lessons about Parisian middle-class social mores and the intricacies of living in a close-knit community such as Les Halles.