This flat is perfect for anyone (individuals or a family, like us) who is spending any time in Paris. The location is fantastic (just blocks away from Gare du Nord and Gare de l'Est). As Guillaume writes the location is in an up-and-coming part of Paris with great restaurants nearby.
Guillaume is a perfect host. The directions on how to get to his place were very clear. We checked in and checked out easily.
The apartment is really great. We had a family of four. Our two kids could have shared a room (with a trundle bed) but one of them opted to sleep on the really comfy and roomy sofa bed in the living room. All of the beds were comfortable and there was plenty of sheets and blankets.
There is a great rain shower as well as a separate bath tub, with ample hot water and impressive water flow.
The main living room and dining area was really open, and it was lovely to spend time there having breakfast or after a long day of sightseeing. There are a great selection of DVDs, games and books (including official programs from Cannes Film Festivals of the past!).
I have been to Air B n B properties all over the world, and this is one of the best. It was a great contribution to our first trip as a family to Paris. When we come back (which we hope to do soon), we will definitely check for availability at Guillaume's place.