I had an amazing four days in Paris with my friend and Pauline's studio we rented was perfect for our stay. Everything in the description is 100% accurate. The studio is small but has everything you need: a bathroom, a kitchen with utensils, a table with two chairs and a sofa bed. It has a big window with a lovely view on rooftop Paris and a church nearby. The toilet is in the hallway (not far away though, you walk 3 steps and you're there) and everything was clean. Pauline offered sheets and towels which spared us a lot of luggage.
The building in which the room was situated was calm (it even appeared as if there was no one else living on our level) and the neighbourhood was lovely with little shops and bistros and beautiful buildings with French balconies :). There is a supermarket very closeby so you can cook your meals yourself which saves you a lot of money. From what we could see, the neighbourhood appeared to be safe as well. The metro Jacques Bonsergent - which is the one we used - is very closeby, we walked 3 minutes at best, so the location is ideal.
The check-in time says 17:00 but we could already check in at 12:00. Both Pauline and her dad (who did our check-in) are very friendly and the communication is clear.
I would recommend this studio to anyone staying in Paris a few days. You pay very little but get everything you need in return. :)