He tried to overcome his dejection by intense work, but he could not forget the tragic suffering he had undergone.  The experience he had recently passed through he disclosed in one of his most noted stories, La Duchesse de Langeais, which he wrote largely in 1834 at the same fatal city of Geneva, but this time, while enjoying the society of the beautiful Madame Hanska.  In this story, under the name of the heroine, the Duchesse de Langeais, he describes the Duchesse de Castries: 

“This was a woman artificially educated, but in reality ignorant; a woman whose instincts and feelings were lofty, while the thought which should have controlled them was wanting.  She squandered the wealth of her nature in obedience to social conventions; she was ready to brave society, yet she hesitated till her scruples degenerated into artifice.  With more wilfulness than force of character, impressionable rather than enthusiastic, gifted with more brain than heart; she was supremely a woman, supremely a coquette, and above all things a Parisienne, loving a brilliant life and gaiety, reflecting never, or too late; imprudent to the verge of poetry, and humble in the depths of her heart, in spite of her charming insolence.  Like some straight-growing reed, she made a show of independence; yet, like the reed, she was ready to bend to a strong hand.  She talked much of religion, and had it not at heart, though she was prepared to find in it a solution of her life.”

In the same story under the name of the Marquis de Montriveau, Balzac is doubtless portraying himself.  It was probably in the home of the Duchesse de Castries that Balzac conceived some of his ideas of the aristocracy of the exclusive Faubourg Saint-Germain, a picture of which he has drawn in this story of which she is the heroine.  Her influence is seen also in the characters so minutely drawn of the heartless Parisienne, no longer young, but seductive, refined and aristocratic, though deceptive and perfidious.

Before publishing La Duchesse de Langeais, the novelist was either tactful or vindictive enough to call on Madame de Castries and read to her his new book.  He says of this visit:  “I have just returned from Madame de C——­, whom I do not want for an enemy when my book comes out and the best means of obtaining a defender against the Faubourg Saint-Germain is to make her approve of the work in advance; and she greatly approved of it.”  But a few weeks later, he writes:  “Here I am, on bad terms with Madame de C——­ on account of the Duchesse de Langeais—­so much the better.”  If Balzac refers to Madame de Castries in the following except, one may even say that he had her correct his work.