I hate that I can't give this flat five stars!
I will start by saying that the communication with the owners was excellent and that they were very helpful. The location is fantastic, truly: it's about a two-minute walk to a major metro station, and it's surrounded by little bars and cafes. At the same time, it's on a quiet little street. Lovely. The bed and couch are pretty comfortable. It's on the ground floor, and it's exactly as pictured.
Still, the flat felt very utilitarian—not like a home. I didn't really want to be in there unless I was going to sleep. Some of this might be remedied very easily. For example, the owners could leave extra towels and sheets; could put books or plants on the shelves; or could put a rug on the floor. (Maybe they have by now!)
Other things would be harder to change. For example, I had to keep the black-out curtains closed all the time because people were always walking through the courtyard. The courtyard itself is full of bicycles and the building's trash bins. The furniture in the flat feels a bit ... not sturdy. Also, the shower really is very small and the door doesn't close all the way.
Again, the owners were great, and some of the above might be addressed by the time you visit! Still, and for the price, I was a bit disappointed.