I enjoyed the stay so much that I could describe the place as perfect. The apartment itself is very nice, clean, big and it completely feels like being at home. The location is also fine- you can get easily to any "places of power" and at the same time during the night the only sound you will hear is birds singing. Unfortunately I haven't met Katrin personally, because she was travelling, but her friends kindly helped me with everything and she as well left me the most detailed instructions for the apartment and Berlin trip. Couldn't be satisfied more. Thank you!