The location is GREAT; Bastille is a fun place to hang out in Paris away from the tourist traps and same-same bistros. There's tons of great food options (always a line out the door at East Mama), and being over a bakery is a big +++. Plus, you're right off the train stop.
As for the space, it's a bit snug but perfect for one or two people. Clean, welcoming, and equipped with all the stuff you need for a pad in Paris. Everything was wonderful, and Prune was super responsive and helpful through the whole process.