Saul's apartment was great for our party of 2 staying 4 nights in Paris. The area is up and coming but it still has a bit of poverty so there are some homeless people in the area. However, we were two girls and were fine getting home late at night. The area also has great restaurants and cafes around so it is a good location for that. There is a metro station about 4 minutes walk from the apartment which gets you to all the main attractions of Paris. It's not right in the centre of Paris but it was easy enough to get around by metro.
The apartment itself was very small. Everything was compact but functional. The kitchen is tiny so it can be difficult to cook but we managed to cook breakfast every morning.
Saul was a great host who was kind enough to help us with our luggage up some stairs. He also suggested some bars for us to visit in the area which was nice. The check in / check out process was easy and communication with Saul was good.
Overall I would recommend Saul's apartment if you are looking for a short stay in Paris.