This postcard is postmarked 1904. The joke is the man pulling the woman's chemise tail, her "Panache blanc", a joke on the white feather of cavaliers. The tail sticks out of her open drawers in the back. The woman's clothing looks old fashioned for 1904 fashionable underwear was basically the same at that time of chemise, corset, and drawers. The chemise tail showing seemed to be a popular joke at the time from illustrations I posted earlier.
Refer back to these postings...