I had a really enjoyable stay at Petra's place. The location in Neukölln is great - just a few minutes' walk to Tempelhof field, and very convenient to public transport. The apartment is a studio, but felt surprisingly spacious, and it was possible to draw a screen to block off the kitchen and windows, for better sleeping. I did not meet Petra, but her neighbor, who met me and gave me the keys, was very warm and welcoming, and told me everything I needed to know about the apartment. I would thoroughly recommend the apartment.