I highly recommend any of Rick Steves' books that has Paris/France in it. I've been to Paris quite a few times, and the first few times I went, I carried this book with me and discovered many easy-to-understand walking tours that he laid out in his book, along with many cool tips about lodging, eating, and sight-seeing. It's also full of money and time-saving tips. Book will run you about 15-20 bucks, but it's definitely a great investment and will make a good read for planning your trip schedule while on the plane.
Bon voyage!!
My personal favorites: P.S. If you're going to be in Paris for 3 days or more and plan to see at least three of the museums, invest in the museum pass. I think you can buy these at the airport and the metro, and definitely at one of the museums.
The Louvre
Notre Dame and Ile de la Cite in general
Montmartre
Eiffel Tower
--definitely have to do a Bateau-Mouche ride on the Seine!
Les Invalides (Napoleon's tomb and army museum)
St. Chapelle