The Duchess of Langeais is an 1834 novel by French author Honoré de Balzac (1799–1850) and included in the Scènes de la vie parisienne section of his novel sequence La Comédie humaine. It first appeared in 1834 under the title Ne touchez pas la hache in the periodical L'Écho de la Jeune France. It is part of Balzac's 1839 trilogy Histoire des treize: Ferragus is the first part, Part Two is The Duchess of Langeais and part three is The Girl with the Golden Eyes.