Very cool apartment; it's a bit rambling and slightly ramshackle, but all done in excellent taste. The location, near Bastille, is fantastic, with great access to many metro lines and lots of cool shops and restaurants nearby. Wouldn't necessarily recommend for the very young or very old (walkup apartment, spiral staircase to upper level, very narrow hallway where you have to bend down at one point so as not to hit your head), although there is actually very serious childproofing in place (and lots of toys), so young kids would not in fact be unsafe. Our 6 and 12 year olds loved it, and it was perfect for them.
The a/c is for real, and a fantastic and hard-to-find amenity for summer visits to Paris.
Overall a superb place and a very good deal.