I grew up learning little about the German colonialism in Africa from 1884-1920, or the Herero and Namaqua genocide between 1904 and 1908 (the first genocide of the 20th century), or the term Rhineland Bastard, used by the Nazis for Afro-Germans.
The Stolpersteine Project commemorates people prosecuted and murdered by the Nazis by placing a brass plate at their last place of residence of their own choice. There are more than 75,000 of them in Europe, in Berlin alone 8587 at the moment. Most of them commemorate Jewish victims. As far as I know, there are three such Stolpersteine for so-called Afro-Germans in Berlin, and another one in Frankfurt.
Martha Ndumbe‘s Stolperstein is in front of a day care at Max-Beer-Str. 24. She was prosecuted officially as a sex worker, which is why her mother didn’t receive any compensation after the war: She couldn’t prove her daughter was prosecuted because of her race.
Mahjub (Bayume Mohamed) bin Adam Mohamed (Brunnenstraße 193) was a soldier and actor. He was killed in the concentration camp Sachsenhausen.
Ferdinand James Allen (Torstraße 174) was the son of a black musician and his German wife. He lived with epilepsy and was first sterilized than murdered by the Nazis.
All three Stolpersteine are in Berlin Mitte and can be visited during a 30 minute walk. There are several others on the way.