1768 Madame de Boufflers et Thérèse by Louis Carrogis (Musée Condé - Chantilly France)
Marie Françoise Catherine de Beauvau, Madame de Boufflers, was one of 19 siblings. She married Louis François de Boufflers (1714–1752), marquis d'Amestranges, and bore him Stanislas de Boufflers, later famous as a poet. Her Wikipedia article is here.
Photo - René-Gabriel Ojéda; some spots in background removed with Photoshop and size increased by half and darkened by gogm.