Oh, how fun! When you're in Paris, do a tour with Fat Tire Bike Tours. They have brochures in most hotels etc. Several tours to choose from, great fun!

Another tip is a card set called City Walks: Paris, 50 Adventures on Foot. We really got some good use out of them last summer, saw some sites off the beaten path, and the cards are really easy to use since you can just slip a few in your pocket for the day.

Oh, and get a 3-day metro pass, well worth the money.