Paris is very expensive and Karine's studio is a great option if you don't want to spend loads of money. It's small but the space is used very efficiently.
Good points: Wi-Fi very good, shower strong & hot, residence overall very quiet so no problem sleeping, located on the ground floor of an internal courtyard so cool at night and during the day. The canal st martin is very nice, great for cycling or walking or having drinks with friends. And you're right next to the gare de l'est, so easy transport links to almost anywhere in paris.
The retractable bed is a nice feature, but you can't use the extra space for anything anyway, so not really important.
Communication with Karine was very efficient & positive, I only needed to speak to her once and she solved the issue I was having quickly.
Overall I recommend :)