As other reviewers have noted, this is a small flat, but it's a pretty normal size for Paris accomodation. I would say it is perfectly adequate, but not outstandingly clean or welcoming. Kitchen not that well equipped (lack of pans, for instance, but then perhaps they expect people to be eating out more in Paris).
It's a central location with several supermarkets nearby.
There is no flat number so make sure you ask for the front door code to get in to the courtyard. We were met by a neighbour because the owners were away but we couldn't get through to start with.
So, I would say overall, an 'OK' stay, but not as pleasant and welcoming a flat as some Air BnBs I have stayed in.