Yes, the market is definitely worth the time. It is like going to a museum of local culture: cheese, freshly baked pastries, horse meat, rotisserie chicken, women trying on lingerie, etc. Also, along the near-by Commerce street there are a lot of small shops, restaurants and caffes. Mostly local crowd, very entertaining. The metro stop, Grenelle- La Motte,is a major crossing of tree major lines which would take you just about to any touristy place in Paris. It is a very easy commute. Enjoy!