The Galeries Lafayette, tree-shaded squares, and Montmartre.
Did I tell you I have been to Paris? :) I know, I'm a bit obsessive, but it was such a pleasant change!
If you are planning on some serious shopping, something to keep in mind: to my surprise, the Galeries Lafayette - department stores not to be missed - are closed on Sunday! ... but of course I have managed to stop by on my way to the airport on Monday!