We had a great stay here. The space is small but worked very well for the 4 of us. There is plenty of room to hang out, cook, and eat since everything is right where you expect/need it to be. Bastien was a great host (he even left us a little treat upon arrival) and was very responsive as well as helpful when we had questions. The location is great - it was nice being so close to a major metro hub.
Both beds are super comfy - always a huge plus when it comes to sofa sleeping!
The six flights of stairs was no issue for us (and that was with the added challenge of dragging over 100kg of bags up and down - we had climbing gear with us that we used prior to our stay in Paris) but it was good to know about prior to getting there.