Claudine-Alexandrine Guérin de Tencin (born April 27, 1682, Grenoble, Fr.—died Dec. 4, 1749, Paris) was a French author and literary patroness whose associations with celebrated writers and political personalities ensured her position as one of the prominent social figures of the 18th century.
Tencin became a nun early in life but soon abandoned her vows in obscure circumstances around which many legends grew. After the death of Louis XIV, she sought her fortune at court and became the mistress of Cardinal Dubois (prime minister for a time), of the regent, and of other influential men. The philosopher Jean Le Rond d’Alembert was her son by one of her lovers, the chevalier Destouches. Falsely charged with murder, she was imprisoned in the Bastille in 1726 and was released only after the intervention of her brother Pierre, then an archbishop and later a cardinal. Thereafter, she sought less scandalous distinction as a hostess. The writers Bernard de Fontenelle, Pierre de Marivaux, and Jean-François Marmontel, as well as the philosopher Montesquieu (whom she twice assisted in publication of his works), frequented her salon. Her best-known work is an autobiographically inspired novel, Mémoires du Comte de Comminges (1735).