We stayed two nights in Tuan-Huy's apartment. Directions for finding it and getting in were clear and effective. It was in very good order when we arrived and the apartment itself is neat and, given it's a studio, gives a sense of space. We weren't at all cramped.
It is very convenient for the Gare du Nord, which is what we wanted, and so has also good links with the rest of Paris by public transit. The area around it is bustling and, during the day, we wondered if it would be noisy at night. In fact, we had no trouble with noise at night and enjoyed the range of restaurants and shops that were causing the bustle during the day and evening.
This was a good choice for us and our needs on a short tourist break in the city.