This studio is an extremely good value. It is small, but with a surprisingly large bathroom. It is clean, centrally-located, quiet, and safe. It has three sets of tall windows, and heavy black-out drapes on two of them. (Not on the court-yard side set of windows, however.) It is also nicely stocked with things; after a little poking around I found an iron, which saved me (I was in Paris for a conference). The WiFi works excellently. Driss, though out of town, was a gracious e-host. The 1st-floor (European) studio looks out on a small plaza, where children play in the day, and young men occasionally drink a beer in the early evening. It is very quiet at night.
The only thing likely to surprise guests is the air-conditioning system. It consists of a three-foot high machine on wheels which serves as both fan and air-conditioner. When used in the latter capacity, the machine has a ventilation tube that must go out the window. That means that at least one tall French window (6 to 7 feet high) must remain open at at least a 45% angle. The air conditioner produces a steady stream of cool air, but with the window open like that, it cannot bring the whole studio’s temperature down the way a more typical air conditioning system would.
A further wrinkle on my trip was that the air conditioner's plastic ventilation tube, brittle with age, was broken in several places and unusable. I contacted both Driss and AirBnb support (as they recommend when an advertised amenity is not working), and within a couple of days Driss’s technician had replaced the hose. It needed a minor adjustment a few days after that, but in general worked well.
Other than that, my stay in the flat went off without a hitch. As I said, it is a very good value, and I would definitely consider staying here again if I travel to Paris by myself in the future.