We had a really nice stay in the small studio of Grégory. We didn't meet Grégory himself, but a man was there, when we arrived and showed us everything. It is definitely a small studio but there's everything you need. The metro République is not far, so you can visit the whole city easily.
The only thing we missed was a coffee machine. Coffee pads are left in the kitchen but we didn't find a machine and in these hot days it has been really hot in the studio. You can open the door and a very small part of the big window but when it's 30 degrees, this was too less.
All in all we can recommend the studio and we would return, if ever coming back to Paris.