Karl Kautsky lived in Berlin-Friedenau for many years; his wife, Luise Kautsky, became a close friend of Rosa Luxemburg, who also lived in Friedenau.
Karl Kautský žil po dlouhou dobu v Berlíně-Friedenau, kde se jeho žena Luise Kautská blízce přátelila s Rosou Luxemburgovou, která žila ve stejné čtvrti.