The place has a lot of charm. I would say the flat comfortably hosts 2. We were x3 with one of us on a fairly comfortable floor mattress, so it depends on your flexibility.
A nice touch was a desktop/wifi to search places to go to. Super close to the train station as well.
We loved most the area, Belleville. Plenty of food options nearby (mostly asian), an artisanal bakery on the same street and a couple of cool wine-bars. Also, a 15/20 minute walk to Parc du Buttes Chaumont on warmer days
Ludovic was quick to respond to any questions we had. Would recommend to travelling friends or couples.