The apartment was very clean and very beautiful, it's located in a very good area in the center of Paris (you can reach a lot of places from there by walking), and it's a 5 min walk from a very big train station and RER.
The apartment is on the sixth floor (there's an elevator for the first 5 floors and then another floor with stairs).
It's a small apartment and felt a bit crowded with two people in it, but it includes all the necessities for the stay, especially if you only plan to spend the night there and travel the city the rest of the day (like we did).
Marc was very kind, he met us on the day of the arrival and helped us with recommendation for restaurants and directions.