St-Ouen Flea Market: Bargain-Hunting Tour in Paris. Discover a bargain hunter’s paradise at Paris’ St-Ouen flea market, one of the largest of its kind in the world. Browse hundreds of unique market stalls accompanied by your local guide, who will help you find what you’re looking for and negotiate the best deals with vendors. Shop like a true insider at the amazing open-air market, which is been in operation since 1885. Group numbers are limited to 10 people for a personalized shopping experience. Book and Save 10%! St-Ouen Flea Market: Bargain-Hunting Tour in Paris.