The biggest draw to this place is the location. It is an under five-minute walk to the Bastille, bus lines, and a Metro station. If you're so inclined, it's an easy walk to the Louvre, Notre Dame, Tuileries, Musée D'Orsay, Bataclan, and the Opera House, among many other attractions. Some excellent restaurants within a few blocks as well.
The flip side is that the location is what you're paying for, not the unit itself. The bathroom is a narrow cement monstrosity, with the toilet tucked into an alcove where you can't sit down without hitting the back of your head on the cement, and the sink is half covered by an overhanging cement shelf. I'm an average-sized guy and I had to move sideways in that space. There is a full bath tub with shower which I found to be adequate.
I didn't need to use the kitchen much, aside from storing drinks in the refrigerator. The cooking surface is a portable, two-burner electric cooktop. There is a small electric kettle, which desperately needs cleaning with vinegar. There were a few staples in the pantry, but I had to buy salt, which I left there (you're welcome). If you're big into cooking you will probably have to purchase many of your own spices, condiments, etc.
The lofted sleeping space has a floor covering which may as well have been sandpaper, which you're required to crawl across to get to the mattress, which was uncomfortable. I put down pillows to crawl on to save my knees. After the first couple of nights I stayed, I moved my sleeping arrangement to the couch which I covered with pillows; I had to sleep half-reclined with my feet on the coffee table since the couch is closer to love-seat-size.
The unit is accessed via a private driveway tunnel that looks like it might be unsafe, but I didn't have any issue with it.
The unit was not quiet while I was there during the day. Children are playing and there is a washing machine in a neighbor's unit that is used regularly and which makes significant noise. If you do sightseeing during the day, but need to take a disco nap before spending the night at clubs, this might be an issue. Conversations in neighboring units are very audible across the small courtyard if you have the windows open, which I did because it was warm and there is little air circulation. At night it was mostly quiet.