Check-in is outsourced to a third party. The person that met me for check-in was late, so I was standing on the street with my luggage for about 20 minutes. I was allowed to check in at 1pm to drop off my bags, so the cleaning wasn't done when I arrived. I thought this was ok, but the check-in person warned me to "hide my stuff" if I wanted to leave before the cleaning lady came, which made me feel like my stuff was't safe in the apartment. I had to stay and wait for the cleaning lady to arrive and clean the apartment. There was some mix up with the keys the check-in person gave me, so I had to sort that out with the cleaning lady before she was able to leave. The hot water wasn't working when I arrived, so the check-in person had to call a technician to go fix it.
There is no A/C in this apartment. A fan was provided, but even with open windows, it was MISERABLE in the heat. I would NOT recommend staying here in the summer.
It would be helpful to note that the stairs up to this apartment are a decorative wood spiral stair case. I was aware that this apartment was on the third floor with no elevator and didn't mind carrying my suitcase up, but the spiral staircase with wavy wooden steps made carrying my suitcase up very difficult and felt kind of dangerous.
The space is very small - it was ok for me since I was traveling by myself, but it would be too small for more than one person.
The washer/dryer were a selling point for me (I wanted to pack lighter). However, the dryer is unusable. I dried my clothes for 3+ hours and they were still wet. I ended up having to hang up my clothes all over the apartment to air dry. The apartment is tiny though, so this made it so that I could no longer use the table, couch, or bed.
The location is good since there are a lot of bars/restaurants in the area, but it is a little removed from the tourist attractions in Paris. Be prepared to spend $30+ USD on taxis to the Louvre, for example.
Finally, I had to checkout 2 days early since my flight was rescheduled, and in my opinion, the host was very unfair about my request for a partial refund. She denied my request for a partial refund and instead offered to refund me only $6 by increasing the price per night of the nights I stayed. I understand cancellation policies are to the discretion of the host, but my interaction with Barbara made me feel that she was being very unfair.

Overall, my experience was pretty bad. The space was so hot I couldn't sleep comfortably, check-in was stressful, and the host was unfair in the treatment of my reservation modification request.