This is one of the oldest streets in Paris. There is a Comfort Inn on "the Mouff" that is reasonably priced. The street is fantastic, mainly pedestrian with lots of cafes, boulangeries, cheese shops, etc. You walk up to the Place Contrascarp, where Hemmingway lived. Near two metro stops. It really is a market everyday- fish, vegetables etc in little shops.
You will find more details on this great Paris market, including recommended shops and photographs at: Rue Mouffetard.
There are also some good restaurants in the area. Try Restaurant Lilane, 8 rue Gracieuse. 01 4 5 87 9 0 68, Métro 7 Place Monge.