Le Rendez-vous pour Marly by Moreau, 1776.
Squire, Geoffrey "Dress and Society 1560-1970" p. 115
Two women in full Rococo gear. Both are wearing polonaises (overskirt + attached bodice) that are tucked and folded to give a "fullness" to their figures, with a whale-bone-reinforced underskirt underneath showing another layer of skirts (petticoats) underneath. Their footwear is still the high-heeled boots of early post-Baroque style, but that would change very soon to low-cut slippers that have flat soles.