It's an amazing place with huge views over rooftops and Eiffel tower. Nicolas is a great host, always replies quickly and super friendly. The actual stairs up to the apartment are shallow so easy to climb but there are lots (4 flights) and no lift. The actual apartment is really nice and has a good self catering kitchen with loads of kitchen ware and spices etc, lots of windows and soace. Comes with a TV and apple TV.
The only issue I encountered was the height of the apartment, I'm 6"2 and due to the slanting and curves of the roof I had to duck a little especially in the bedroom/living space. I could stand easily in the kitchen but had to stand at a slight angle when using the sink. This was only a minor issue as we only stayed 2 nights, but if it were much longer i would have struggled.
Overall definitely great value and a recommended place to stay.