Born the daughter of Louis François Armand de Vignerot du Plessis, Duke of Richelieu, and Princess Élisabeth Sophie de Lorraine (daughter of Joseph, Count of Harcourt), a French prince étranger, she was raised with her paternal aunt in a Benedictine convent.

She hosted a salon which gathered "the literary celebrities of the days", including Voltaire and Rousseau, and was a center of opposition to Madame du Barry.

[1] Through her close friendship with the Swedish ambassador to France, Ulrik Scheffer, she came to know the future Gustav III of Sweden during his visit to Paris in 1771.

[2] She advised him to "repress the strife of the raging parties", advocated a "monarchy restrained by laws" and greeted his coup of 1772 with joy, especially its non-bloody character.

[4] Rousseau visited her at her Château de Braine in 1771, where he recited his autobiographical work Confessions.