This is probably Angélique Louise Sophie d'Allonville de Louville, marquise de Baglion. If so, she was daughter of Charles d'Allonville, marquis de Louville 1664-1731 and Hyacinthe Sophie Béchameil de Nointel 1690-1757 and the wife of Pierre François Marie de Baglion, comte de La Salle (married 10 June 1733). From madameguillotine.org.uk/2011/07/18/.jpg; image size doubled by gogm.
This portrait of the Marquise de Louville is almost a clone of Rigaud's 1711 portrait of Marie Madeleine Coskaer de la Vieuville Parabere.
Keywords: Rigaud, Marquise, French, long straight coiffure, floral headdress, scoop décolletage, chemise, lace, elbow length under-sleeves, engageantess, split bodice, lining, elbow length full sleeves, belt, full skirt, brooch, clasps, wrap