While studying fashion through the 19th century, I came across this old Vogue-cover from 1919. Even though the illustration is a 'close up', you can immediately tell that the girl was an early adopter of the garçonne look, which was introduced by Coco Chanel during the Roaring Twenties.
The illustration is by Georges Lepape, who also did the artwork for Paul Poiret, featuring his "robe à la minute" (1912-1914). As you can tell, this is a simple 'tube'-dress with short sleeves and very narrow around the ankles and in which no corset was needed. Both Poiret as Chanel are considered as the fashion designers who liberated women from tight undergarments.