Answer by
toastedcheese (216)
There's the classic striped black-and-white shirt, beret, red scarf, and black pants. Carry a baguette and say "Hon-hon-hon" a lot. Avoid interacting with actual French people.
Other possibilities - mime, French maid, 18th-century aristocrat (like Louis XIV or Marie Antoinette.) This last option could be quite lovely, although you'd want to rent a costume.