Twelve Bezirke (Mitte to Treptow-Köpenick) plus well-known Ortsteile such as Kreuzberg and Prenzlauer Berg. Prices and rents split sharply between the S-Bahn ring and the outer east.
A purchase is notarial: Grundbuch, ~6% transfer tax in Berlin, notary and registration on top. sivrce will not publish a Berlin listing we cannot verify.
Until then this page is the orientation layer — linked from sivrce.com/de — not a duplicate of sivrce.ge.