In the early 1700′s the loose fitted, Sacque gown (aka robe volante or robe battante) gained popularity. These gowns draped from the shoulder to floor, typically with double folded pleats known as “Watteau Pleats”.
Some people believe that this style gown is evidence of a lack of etiquette within french court while waiting for Louis XV to grow up after his fathers death. I can see the appeal in wearing robe volante to court. It’s basically wearing a giant tent. It appeared to be a relaxed look, but women still wore stays under it.
Later, Sacque evolved to the robe a la Francaise- a fitted bodice front with the Watteau back.