I will throw my 2 cents in for a few sites:

With the limited time, I would go to Notre Dame, walk up the banks of the Seine to Musee d' La Orange (BadgerBoi can correct French spelling). Great Monet paintings there and I found it overlooked by many (or at least not nearly as crowded as the Louvre). Same for the Musee d'Orsay. Not nearly as crowded as the Louvre but could be busy. You can book online a time to visit the Eiffel. You get a reservation for a specific time and get to the skip the very huge lines there. If your interests are in the world wars, go to Hotel d' Invalides and the Army museum. The museum covers France's history in both wars. Located very close to the museum, is the Rodin Museum. Again, it wasn't crowded at all (it was Sept when I went there). A key to museum entrances is if you get the museum pass, it allows you to skip most of the lines. You could also use the metro to get around. I found it extremely convenient and fast.

Enjoy your time in Paris. Make sure you make plans to go back and spend several days there. You will be hooked for sure.