This empty frame is more interesting than you think! It used to hold Jean-Baptiste Greuse’s La laitière (painted some time between 1750 and 1775)—but it’s from the 19th century, made in the style popular under Louis XVI. So it was chosen to match the painting and that worked pretty well, but the Louvre curators then managed to get their hands on a genuine 18th century frame, which is now paired with La laitière.
There were a bunch of other empty frames on the same wall, probably similar success stories. It just goes to show, art is a process too. It can reframed (literally!) and recontextualised over and over.