I beg to differ with our friend who said a 6-year-old wouldn't enjoy the Paris sewer museum. Our 4-year-old son loved it; he pretended to be a sewer worker for the rest of the day!

However, if you only have two days in Paris, I wouldn't consider the sewer museum an important sight.

Someone suggested taking a bus tour, and for a very short stay I think that's a good idea. There are several companies (Les Cars Rouges comes to mind) that offer two-day passes where you get on and off the bus at the major tourist sights, and have a taped guided tour while you're on the bus. The bus is a great way to see the city in a short time. Fare is about 22 euros, I believe.

Bons voyages! Evan in Paris