The best thing about this place is the location. It is close to Metro, shops, cafes, and the Louvre.
The room/flat was really small and even though it might advertise having enough beds/space for 3 people, it was difficult with just my mom and me. We were constantly bumping into each other, and with two large suitcases on the floor, it was hard to get around! We didn't spend much time there during the day, so it was okay.
My mom is really sensitive to smells, so she was up at all hours of the night with neighbors cooking. I didn't have a problem with it, but something you might want to consider if you have a sensitive nose.
There was mold in the shower, which was unfortunate, and the shower curtain smelled like mildew.
I had the top bunk and actually slept really well every night we were there. I thought the bed was comfortable.