This was definitely a great stay for us. As the other reviews have said, the location cannot get better than this. It was our first time in paris and we were really just looking to do touristy things so for us it worked out very well. The place is clean, and the owner is pretty good with responding to messages so thats a plus incase you need any help.
Reason for the 4 starts instead of 5 is that the hallway to get to the apartment is DARK. There are temporary light switches along the way that you need to press but we were carrying big bags and a small kid, and the lack of any automatic lighting made it unnecessarily difficult to get in an out. The other quirk is that hot water seemed to only be available in the AM. It has a local water heater thats supposed to replenish hot water in a couple hours but it didnt work for us until the next morning. If you're the type to take long showers the next person is out of luck.
Other than these two things, its a pretty great place to stay.