Paris is one of the world's most romantic cities. You could spend a month and not be tired of it. Visit the greatest art collections in the world. Discover the birthplace of Impressionism. Ride the elevator to the top of the Eiffel Tower. See Notre Dame. Eat steak tar-tar. Be polite to the Parisians.
Imagine yourself living in the French Revolution, kicking marie Antoinette's head down the Champs-Elysees. History isn't pretty, but it sure can be fascinating. Have a great time - remember you don't have to see everything, come back again.