you're really missing onto something if you don't attend the Marché aux Puces in Place Jeu de Balle! the surroundings are quite off the tourist paths which is always a plus to me, and from 6am to 2pm every day (3pm during weekends) they've got this flea market going on. piles of useless stuff, but ...take your time and you'll discover some little treasures! i've got myself a vintage dress for a ridiculous price, couldn't afford to buy more for i was travelling light and had no room in my hand luggage. too bad! after you're done with the shopping, there's some tiny bars all around the square: you can grab a snack or sit down for a coffee and enjoy the lively neighbourhood.