We had a very interesting stay here.
The bad:
the building in which this apartment lives is pretty dingy. The walls had unsightly stains and the building had an off odor generally. You need to keep the bathroom door open or it starts to stink pretty badly. Additionally, a lot was made to us about the need to be quiet during certain hours. While that isn't a problem, the other tenants certainly don't abide by these codes as on both nights of our stay, we could here people yelling at each other out in the courtyard.
Additionally, we had a bit of a scare in the apartment that pretty well ruined our night. We resolved it with our hosts, but communicating about the issue was very tense and difficult.
The good:
Wi-fi in the apartment was fantastic; very fast. The apartment itself was quite clean and, except for our issue, the hosts were very helpful. Communication on how to check-in was very clear and and easy to follow. The apartment is in a pretty good location; easy to get around the city.
Overall:
It's a quaint little apartment with some certain issues. But, if you are looking for a cheap place to stay in Paris, it's a good spot.