The guide I have recommends going to Rue Cler first. It says that visiting this area serves as a good introduction to Parisian culture. Sounds wonderful to me, and since I've never been to Paris, a good way to start out.
According to the travel book that I have, a very good walk to do is from the Arc de Triomphe to Tuileries Garden. There are numerous sights on the way, but it might be better to go to the Louvre first and then walk to the Arc de Triomphe. That way I will be at the museum early enough to avoid crowds.
