Great, although tiny, apartment just behind Moulin Rouge. I'd say it is perfect for two but worked well for four - we spend 99.9% of our time exploring Paris anyhow and just came home to sleep.
I think its a fun location to start into Paris sight seeing, however, this also means its a touristy area. For us it was great and the possibility to self check-in and out was great, easy, and very flexible.
I would totally recommend it.