What an excellent location, right in the heart of Paris. Close to restaurants and you can walk to St Michels and Notre Dam (about a 30 minute walk) from here.
There is a single mattress on the floor on which you will sleep. The room is tiny but it is as expected. The only negative is that I didn't sleep a night uninterrupted, as you will hear noises transmitted up the public staircase and also if Marie comes in late she will need to walk through the living room to get to her room so I did wake up a few times, but it was ok and I managed to get back to sleep in the end :)