This is a decent place to stay in if you are visiting Paris just for a couple nights, but I would not say it is suitable for longer than that.
There were a few pros: it was very close to the Metro station, the locks felt very secure, and the small balcony had a decent view. Beatrice is also a very nice host. Checking in and out was very easy.
However, there were also some cons. For one, there is no air-conditioning... while there is an AC unit there, it does not work. We were surprised by this especially because we visited Paris during the hottest time of year. We were sweating a lot during night and day, so definitely expect that if you are visiting during July -- still, I believe this is noted in the listing, so I can't complain there. It's just something to keep in mind.
Secondly, the room was much smaller than expected -- the shower is just directly in the room, meaning you can step out of the shower and step right into bed. Because of this small space, it was difficult to really walk around. It felt especially cramped because we could not open two full suitcases and lay them on the ground. This made the overall place seem small.
In sum, the things we did not expect were: very small space, no soap, and limited toilet paper.
Overall, this is a great choice if you are looking for something on the cheaper side. But, if you are visiting Paris for the first time, or you have more than one large suitcase, it may be more comfortable to stay elsewhere. Nonetheless, we are happy with our stay for what it was, but we do think that if we returned to Paris, we would pay a little extra to stay somewhere else.