Staying at Dominique's place was a "mix-bag" for me. As for location, since it is the 18eme it is touristy, the street that the apartment is on is busy, and has quite the night-life.
As a female foreign solo traveller, I felt a little unsafe walking at night to the apartment from the nearby metro stops - you have to be on extra alert at night, because the Sacre Cour area is where many thieves go for a larger tourist foot traffic. There was more than one occasion where I was targeted by men prowling on the non-locals for one reason or another. Dominique assured me it was safe, but maybe safer for locals who are completely familiar, so just be aware if you're traveling solo as a woman.
Dominique was helpful when there was some issues with my stay overall. But the room I stayed in was very cold at night. She might of had an issue with the heater when I was staying here, but Winter had set on, which makes it hard to sleep if you're not accustomed to the cold. When I asked if the heater could be turned up/on in my room, Dominique was not very helpful, and ignored me. Since she wasn't helpful I had to be proactive to see if I could turn it up myself, which then she had a very nasty and irate response for me, yelling at me, and telling me not to talk to her at night (when she was up and about in the apartment), I would not have bothered to ask her if I wasn't freezing in my room. So this attitude from Dominique definitely took off some stars to put it simply.