We really enjoyed the apartment. The living room and kitchen are very spacious. It was clean and well supplied. It was nice having the courtyard as well as the toys available for our young travelers. There are several great restaurants, shops and grocery stores close to the apartment.
The pullout couch was not working properly and was extremely uncomfortable. The other beds were comfortable but we had 7 people and needed all of the beds.
The apartment is well connected to public transportation. The walk to the Marx Dormoy metro stop feels much nicer and safer than the walk to Gare du Nord (there are several homeless people sleeping on the streets in that direction). We were with a group and didn't feel threatened but would not want to walk that way alone.