This is a wonderfully located apartment in the centre of town. Close to metro and RER stations as well as the Lourve and all the food and fun that is Rue Montorgueil.
The showers are strong and the beds comfortable. The kitchen works reasonably well and they've managed to sneak a clothes washer in. There's excellent air conditioning in every room.
The downsides are, 1. Size. There is very very little common space in this apartment and the bedrooms and beds are really only suited to one person in each room. (There is physically no room for the luggage of two people in one room) and the apartment, with no windows to proper daylight fast feels a little claustrophobic with more than 4 people. 2. The apartment faces the internal open area of the building its located in. The windows are all, necessarily, frosted. So once your inside its dark and quite airless.
Overall a great base for a short stay for no more than 4 people comfortably. Represents great value for money with a responsive host.