Me and three other friends stayed at Em's place for almost a week and had a great experience. The apartment is located in the trendy Bastille area, super quiet but also near the local bar scene if you like going out. It's also near three different metro stations, which was super convenient since we took the metro around the whole time we were in Paris. My friends who stayed on the sofa said it was one of the comfiest sofa beds they've ever slept on.
Josepha, Em's mother who lives upstairs, checked us in and was super friendly and an overall lovely person. She was quick to communicate and help us with check-in, even though we arrived at different times. Everything was clean and provided for us in terms of sheets, towels, soap, wine opener (important!), and even shampoo and conditioner. One thing to note is that the apartment is on the 5th floor. Really it wasn't a bad workout at all, but just note that there's no elevator! Would definitely recommend staying at Em's place if you want to stay in a more local and trendy area that's close to great restaurants (Chez Janou is only a 15 min walk away) and metro stops.