The two Ladies are Caroline de Murat (not Napoléon Bonaparte's sister), Marquise de Pezay, and Victornienne de Rochechouart de Mortemart, Marquise de Rougé. There are French language Wikipedia articles about the Marquis de Pezay and de Rougé.
Upgrade image from Athenaeum posted on 28 November 2012.
This group portrait is a showcase of pre-Revolutionary dress with at least one sheath, long tight sleeves, striped fabric, and curly coiffures encased in a wide cap and a wide turban.
Keywords: 1787, Vigée-Lebrun, Marquise de Pezay, Marquise de Rougé, Murat family, de Pezay family, de Mortemart family, de Rougé family, Marquise, French, long bouffant coiffure, cap, turban, scoop neckline, bertha, long tight upper puffed sleeves, cuffs, long close sleeves, waist band, full skirt, sheath dress