A favorite small museum of mine is the Musee de Cluny. It is the museum of the middle ages. It is pretty close to Notre Dame on the Left Bank. It was an old monestary (or convent, forget which) and is on a site occupied since the early days of Paris. It was built on top of Roman baths which have been restored in the basement including some statues from the time of Augusta. Another interesting thing are the heads from some of the statues on the outside of Notre Dame. They were ceremoniously beheaded during the revolution because they were thought to be statues of the nobility. The heads were buried and turned up many years later. They are on display here. Also lots of stuff from the middle ages. The highpoint is the tapestry "The Lady and the Unicorn". Fair amount on the web about this such as http://www.licornedecluny.com/GBpage...amlicornGB.htm. But I found it really wonderful.

For a nice walk I would suggest the Mouffatard walk. Starts near Notre Dame/Sorbonne and goes through some real nice neighborhood for walking and markets.