Great place -- very stylish. The Futon DOES fold out, but can be a little tricky to figure out. Luckily the housekeeper saw we were a party of three when we came to drop off our luggage, so she pulled the futon out and presented the place to us as a two-bed.
Great location, very stylish apartment, and very close to great restaurants such as Mahkeme Locantasi and other small pop-ups, in addition to a short walk from the bridge and the Galata tower.
I recommend staying here!