We stayed at Arnaud's apartment for ten nights. It is perfectly located, both to enjoy the area of Montmartre and Pigalle, and to get around the city.
We didn't get to meet Arnaud, but he responds quickly to messages and is very easy to communicate with. When our flight was delayed he even managed to come up with an alternative solution for us to get the keys.
We were unlucky to have workers right outside the bedroom window during our stay, but that's not Arnaud's fault, and hopefully they are done before the next guest arrive.
Be aware that there is some pretty steep stairs to get from the front door and terrace to the apartment. That was no problem for us, but it might be nice to know. Also, if a firm bed is not your thing, this might not be for you. The layout of the apartment is very good, especially if you plan for a longer stay.