This apartment is in a picturesque neighborhood between the Barbès-Rouchechouart and Anvers Metro stations. There were not a lot of other tourists in the area, as far as we could tell, and pretty much all amenities one could need are in the immediate area. The building is a walk-up, but there is a small (two-person) elevator for five of the six floors, which was helpful in ferrying groceries up to the apartment. The neighborhood was very quiet, so sleep was very peaceful. Everyone in the neighborhood was very friendly to us, mostly non-French-speaking Americans.
Note for Americans: the listing notes two baths, but they are two rooms, one with sinks and a bathtub, and the other with a sink and a shower. There is only one toilet, but it is in its own room with a small sink for washing hands. My family of four had no problem with it, but I thought I'd note it here, since in the U.S. "bath" usually implies having a toilet.
The apartment itself is spacious and tastefully appointed. It was cold in Paris while we were there in December, but the space heaters were up to the task of keeping us warm, and extra duvets were also available for us. Florian and his family were kind enough to leave us a bottle of champagne, as well as some coffee and tea, and some other food. This was appreciated, jet-lagged as we were.
This place was a great base from which to launch explorations of Paris, with the two metro stations only about 2 to 3/10ths of a mile away on foot.
In short, we would happily stay here again.