This is a wonderful and very unique space in a small enclave of apartments set between Avenue Junot and Rue Lepic. It's less than a 5 minute walk from the main plaza on Montmartre. Restaurants, groceries, and other shops are very close.
The apartment itself is very spacious. One double bed is in a loft above the living room. It has a very low ceiling (too low to stand) curtains for privacy and to block light, and is accessed by a ladder/very steep stairs. There are two bedrooms with doors and several more mattresses you could use. If everyone needs privacy, you have three separate spaces. But if not, there is plenty of room and beds for probably 9-10 people.
We stayed as a group of 3 colleagues of mixed gender and enjoyed our stay very much.