We liked our stay at the apartment, however, some things were disappointing.
The kitchen utensils were very dirty, we had to buy dishwashing soap to clean it.
The wi-fi was very weak because it was public. Also, only one device could access at the same time.
The hot water didn't last very long (10 minutes maybe). On the first day we had to shower with cold water.
Despite all of this, we think that Nathalie's AirBnb has a great location (5 minutes walk to the opera, 25 to the Louvre, and 30 minutes or less to every other attraction by metro) and is very comfortable. Her brother, Luc, welcomed us and was very nice, and the check-in and out were perfect. We were able to do a late check-out since our flight was only at night. Although we had some problems, all of them can be easily fixed, and we hope that with our recommendations the next visitors can have an even nicer stay.