The one mis-step in the film is luckily in a short scene -- Marie-Antoinette randomly wears an at-least-5-years-out-of-style high wig that is far too pyramidal in shape. Compare it to the far right fashion plate, which is a good representation of the typical late 1770s style. That being said, I have seen wigs that point up like this in back -- but generally they have a ship or some other decoration that works with that shape.