Abstract: The text by Balzac that most captured Proust’s attention is the novella Les Secrets de la princesse de Cadignan, analyzed by Charlus in Sodome et Gomorrhe. It deals with several themes that were sure to interest the author of the Recherche: the Faubourg Saint-Germain, mimetic desire, and the role of imagination in love. Moreover, it touches on the motif of secrets, which would become the focus of the interpretation of Balzac that Proust offers us in his novel.