I stayed at this flat for the entire month of October while I took a French language course, and I loved it! The location was perfect with the stop for Couronnes (Line 2) just across the street from the building and stops for Ménilmontant (Line 2) and Belleville (Line 11) just a few minutes away when walking. It's easy to get there from CDG airport by taxi/Uber (for around €45-50) in about 40 minutes or even by the Metro/RER (for about €10) in just under an hour. The building also felt very safe with key card access at the front entrance.
The flat was very clean and spacious with a breathtaking view of Sacré-Cœur. I loved hanging out there just about as much as I loved walking around the city because it was so comfortable and lovely. Not to mention, it had everything I could have possibly needed, including a washer/dryer. There was also an electronics store and a shoe store just downstairs, both of which were very helpful during my stay!
Arno was very communicative and made the check-in and check-out process very welcoming and easy. He also provided me with a list of great recommendations for restaurants, bars, etc., that was extremely helpful throughout my stay. Honestly, I don't think I could recommend this flat highly enough, and I would love to stay there again in the future!