I got this list from a friend of mine who has in turn, got this list from a travel book some time back.
Arc de Triomphe: Must go. Never tell others you have been to Paris without visiting this.
Champs Elysees: Recommended to walk from Lourve to Arc de Triomphe through Champs Elysees. You can stop by the LV building and Adidas.
La Conciergerie: Optional stop.
Tour Eiffel: Again, must go! Try to plan for this at night.
Lourve: Da Vinci Code... Mona Lisa.... I think there is one weekend where all museums are free to enter. Try to check this out!
Notre Dame: Gothic feeling. It's a must go!
Sacre Coeur: I was told the view is good and there are good souvenir shops around. Moulin Rouge theater is nearby too.