Paris

In July 2004, we visited Paris.  The primary reason was to see the display at the Louvre "Paris in 1400", but also to see as much cool medieval stuff as we could.

The Louvre museum  (although we couldn't take pictures of the special exhibit).
Various sites around Paris, including the Eiffel Tower, the Basilique of St. Denis, and the Arc d'Triumph.
The cathedral of Notre Dame
The Cluny Museum or Museum of the Middle Ages (Museé de Moyen Age)