What are good themes for a fancy restaurant?

You didn't type enough information, so what I thought you meant was either-

Mexican

Boat

Forest

Italian

Chinese

Sea

Dark

I know this is a bit strange but there was a restaurant themed as bathrooms!

I don't remember where but its kinda cool, I read it in a record book.

The seats are toilets, the tables are sinks with a glass pane covered over it, the dishes are mini square plates, the bowls were glass and the cups were little mini toilets with a tiny tube coming out of it.

Hope this is what you meant :)