My one lasting regret from the last time I "lived" in Paris was that I never made it to the D'Orsay. It was ... predictably great. They have a wonderful pre-abstraction Mondrian. Can't post any of my pictures yet as I have no card reader (doh!).
I can't figure out when French people eat out. All of the cafes are packed, have great menus, but no one ever has food on their table, just beer or wine.
Speaking of, the beer in Paris is piss. That's about the only disappointment so far, except the fact that French people's idea of what constitutes an electrical socket is a sorry joke.