By all means go and see the Eiffel Tower, but don't climb it. It is one gigantic rip-off. The entry price is extortionate and the staff shove you into the lifts like cattle. There is nothing to see, except that on a clear day you can see over Paris from the viewing platforms. This is not just my opinion, it is the opinion of Parisians in general. There is Notre Dame and Sacré Coeur, also the Père Lachaise cemetery where many famous people, not just French, are buried. A thirty minute train ride from Paris will bring you to the Chateau de Versailles. However, for entry to Versailles and the Louvre, be prepared to queue for a very long time. Entry to Versailles used to be free on Sundays but I don't know if that is longer the case.