Robe à la française
mid 18th C.
A robe à la française, to add to the terminology, is one with what is often called a “sacque” or “sack” back. While the dress still fits the form of the stays (usually with the help of interior laces), there are extra folds of fabric that hang loose, all the way to the bottom. This is generally popular in the early 18th century, and by the 1760s and 70s, gowns had switched to a the “à l’anglaise” fashion, which was tight against the back.