How does one dress for a real, serious art auction?

Please mention if you are just guessing or you really know.

I saw a notice in the newspaper about the upcoming auction of a collection of fine art, jewelry, Persian rugs, and other treasures owned by a prominent plastic surgeon who is retiring following a divorce. The list of art works reads like a catalog of the Louvre: Rembrandt, Morisot, Sisley, Chagall, Renoir, Matisse, Monet, Toulouse-Lautrec, Picasso, Dali, and more. It is being held at a distinguished location, so I think it must be what it seems to be.

I couldn’t afford to bid on a paper napkin used by Toulouse-Lautrec, never mind a painting by Monet. I would love to go during the pre-auction viewing hour just to see the display. Assuming I’d even be admitted and not barred from parking my ten-year-old Nissan, what should I wear?