The flat is very similar as to what you see on the pictures. It is true that first thing you think when you get there is that it's not what you were expecting. The flat is spread through 3 different floors and there're a lot of stairs to go up and down. Once you enter the flat you have to go up around 10 steps and you have a little toilet (the light was not working there, but it was a nice toilet to use during the day as it had a window and natural light came in). You then go up another 10 steps and you have the first floor. in this floor there's the main bedroom with a wide dressing room connected to the main room with a double bed and en-suite bedroom. Going up another 10-15 steps you had the main floor with the common area: living room and kitchen. In this floor you then had a wodden staircase that took you to the loft-type japanese bedroom (mattress on the floor). Just as a note, there aren't any doors, just on the toilet and bathroom, so there's not much privacy.
other than this, the apartment is great, located in the best area of paris, in a really safe building and Harold had left us some ammenities (breakfast, shapoo and shower gel...) in the apartment.
I would defenitely come back, however I would recommend being up to 4 and not 6, to have more space and privacy!