Mitterrand branch of the Bibliothèque Nationale de France, Paris, designed by Dominique Perrault.
The towers, which are meant to look like four open books, surround a courtyard with a small forest that was shipped in from Normandy.

Tips for Paris-bound geeks: A company called HotCafé has been putting WiFi hotspots, most of them free, in a bunch of Paris cafés. The McDonald's hotspots are also free here, but the croissants are not going to be as good. For dial-up there are "free" ISPs -- you pay for a local call, and the ISP gets a cut of that. I have had good luck with FreeSurf.