My rating of 4 stars is based on two things.
Nadar as a host - 5 stars. He was very friendly and took us last minute (same day) with a late check-in and early check-out. I was fine with that due to us booking late. He helped us with parking (which was free and on the same street) and told us to call him and ask him if we needed anything. There was also water bottles and sodas in the fridge for us to enjoy.
The place it self was 3 stars. We were informed not to open the window as there was construction going on in the alley, due to the amount of dust. They also started work every morning before 7am (literally on the other side of the wall next to the bed). It was pretty hot in the apartment, but there was a fan, which would have been ok if it didn't make a squealing noise every couple minutes. Very tiny place, but ok for a single person or a couple. Bathroom was extremely tiny as it was just a toilet and shower. I had to sit with my legs in the shower while going to the bathroom, that tiny. The place was clean and the sheets were clean, probably the most important in my eyes. The price was right so I wasn't terribly disappointed with these things I spoke about.