Philippe Angélique de Froissy (1702 – 15 October 1785 in Paris) was an illegitimate daughter of Philippe d'Orléans, the nephew and son-in-law of Louis XIV of France. She was comtesse de Ségur by marriage, and a courtier of Louis XV, her cousin.
Her mother was Christine Antoinette Charlotte Desmares (1682–1753), a beautiful actress ("tragedienne") of the Théâtre-Français who was painted by Jean-Baptiste Santerre.
Charlotte Desmares was a niece of Marie Champmeslé and one of the many mistresses of the regent, Philippe d'Orléans, around 1702, the year their daughter was born. Also born in 1702 was another illegitimate child of the duke, Jean Philippe d'Orléans, by a lady-in-waiting, Madame d'Argenton. Angélique's half-brother was legitimised in 1706, whereas Angélique was neither acknowledged nor recognized, although Madame du Prat erroneously states in her memoirs that she was recognized on 22 April 1722, the same day as the abbé de Saint-Albin, another illegitimate son of the Duke of Orléans by his mistress Florence Pellerin.
Madame de Ségur belonged to the inner circle of Louis XV's intimates. She is described as "fresh, white, well made, strong and intoxicating".
She married Henri François, comte de Ségur (1689–1751) at Cagny or Paris on 10 or 12 September 1718. He was the son Henri Joseph, comte de Ségur and Claude Élisabeth Binet.
Called le beau Ségur ("the handsome Ségur"), her husband had been "master of the wardrobe" of the Regent (maître de la garderobe du Régent). He lived in an hôtel in Passy, Paris on a beautiful ten-acre property, which later passed to the Duchess of Valentinois and was named Hôtel de Valentinois after her. (The property is famous for being the residence of Benjamin Franklin for nearly ten years.)