As a woman travelling alone in Paris, it was very important to me to stay someplace where I would be comfortable and feel secure.
This flat is in a lovely part of town - Boulevard Voltaire is a nice wide boulevard with lots of families strolling up and down, yet there are plenty of cafes and nightlife as well. The entrance to the building is on a quiet side street, so it is easily accessible and feels private. The noise from the corner cafe can go on until 1 am on the weekends, but the windows in the apartment are very high quality and the sound was never a problem for me.
Even though there is a facing building on the opposite side of the street, it still gets plenty of light through the three picture windows in the living room. The building is very nice. The amenities in the flat are basic, but I appreciated the hairdryer and the french press. It's a three floor walkup.
I was attending a conference while I was in town, so I appreciated the extra space in the living room to work. I was very comfortable overall and felt very safe.
The toilet is a bit fickle and all of the plumbing runs on grinders, which means there is a bit of noise involved in flushing and showering, which may or may not bother the neighbors. Vincent recommends not using the plumbing in the middle of the night, so I adhered to that. I didn't really notice hearing any of the neighbor's plumbing, so I wasn't too worried about it when I had to shower very early.
A few great points about the location: The Charonne metro is very close. If you can't get somewhere on the 9 line that runs through Charonne (this is the line which also goes to Trocadero/Eiffel Tower), you can connect very easily at Nation, where many lines run. Ateliers des Lumieres is walking distance and definitely worth a trip. I found Le Pure Cafe (featured in the movie Before Sunset) about a five minute walk from the apartment, and it was a great spot for working and coffee (and probably dinner too, although I didn't make it there for dinner). Bastille is about 20 minutes by foot and the city center is about 45 minutes by foot. It's also nice to be somewhat close to La Villette and the Canal St. Martin. I was worried that the location would be inconvenient but I never felt that way. In fact, I was always surprised at how easy it was to navigate back to the apartment from many different points in Paris.
Vincent was very responsive the entire stay and I had no problems. Would recommend.