Don't hesitate to book a tour with Mariana. Really! She has a wonderful bubbly personality and oh so knowledgeable about the market, vintage shopping, and Paris as her second home (she is originally from Brazil). Her communication beforehand was very helpful as we planned our trip to Paris. She is fluent in both French & English. We took the Metro and she met us right on time. We booked a private tour since we were looking for specific items (smalls, art pallets, chatelains, ephemera, cool vintage "stuff.") She had already thought through the best booths to take us to, and she knows a lot of the vendors which helped when we were negotiating. I can't imagine booking anything less than 3 hours; not only did she provide just enough history to make it memorable & interesting, she provided negotiating tips, and best areas to focus our time. We spent the rest of the day there. So worth it to have a guide, and she made it really fun.