We enjoyed our stay here at Jonathan's place. It was a wonderful place just a few blocks from the Sacre Coeur and famed Montmartre district. It had a wonderful balcony you could sit on and enjoy the sights and sounds of a community filled with culture below. A few driver's (Uber, cab, etc.) warned us of the immediate area but we felt completely safe. As with any place, you just need to always be aware of your surroundings and be smart about how you handle yourself.
The apartment was extremely clean and had all the amenities you could want, sans A/C. But we soon learned that A/C was a rarity in France and the weather just happened to be warmer than usual during our stay (late July). But in the evenings, with the windows open - it was sufficiently comfortable.