Ladurée @ Harrods
Ladurée is one of my favourite Parisian tea-rooms. They've recently opened a branch in Harrods in London, their first outside France. It's a jewel of a place, with little linked salons in the style of Napoleon III, serving excellent teas, faultlessly French light meals and some of the best patisserie you'll find in London.
Eating at the tea-rooms themselves is a lesson in luxury. Each salon is decorated in a different style; this is the Black Salon, a tiny room packed to the gills with Etruscan caryatids. Zeus, surrounded by snakes, glowers from the middle of the cupola in the ceiling. If you visit Ladurée, ask for the violet-scented black tea.