If you're really into history and/or art I would reserve one day just for Louvre.If you like skyscrappers and modern architecture you might want to take a short visit into the La Defense hood.
Also, a small advice: don't go on the top of the Eiffel Tower, instead go for the top of the Montparnasse Tower. It's taller and you can see the whole of Paris, Eiffel included. :)
Also, a small advice: don't go on the top of the Eiffel Tower, instead go for the top of the Montparnasse Tower. It's taller and you can see the whole of Paris, Eiffel included. :)