Paris is great if you want something with a lot of history
The Louvre - Art till it comes out your ears
Hotel des Invalides - Museum with loads of armour
Palace of Versailles - Just outside Paris, but awesomely excessive palace of the the Louis'
Champs Elysees - great for just a walk in the evening
Musee d'Orsay - Another Museum with loads of exhibitions throughout the year
Eiffel Tower - Awesome view
Notre Dame Cathedral - Lovely cathedral that Quasimodo went deaf in
Also near the latin quarter where there are some lovely restaurants.
I could go on and on. I for one love it and as a bit of an art buff cannot get enough