I liked the apartment, it was super quiet (aside from hearing people going up and down the stairs but nothing major). Although it's right off a busy street, I liked secluded pretty alley way where it was located. A few people mentioned prostitutes' and yes, I also saw them but they mind their own business (I only saw one at a time and they were just leaning against a wall). Lots of locals doing their delivery, shopping, eating in cafes, etc. The street felt very safe. I was by myself and no issues at night. I liked all the different food places, easy of transportation options nearby.
The place was great for one person, for a couple I could see it being a bit tight space in the bedroom. There's no space for night tables and the mattress is against the wall, with only one side possible for getting in and out of the bed.
The bathroom sink is also pretty small, but typical for European bathrooms. There's lots of storage under the sink. It's located on the first floor so you do have to carry your luggage one fight of stairs. The kitchen in nice, large refrigerator.
The checking process was not the best. Although the instructions were super easy to follow, it was not ideal as a single person to have to go with your luggage to go to another street to get a lock attached to a random pipe and do the same at checkout.
I had a nice stay, I enjoyed my time in Paris and in this apartment.