Hermann Mayer was a son of Leonard Mayer and Flora Sostberg. He married Helene Freudenberg on 20 July 1920 in Zehlendorf (Germany), a daughter of Hermann Freudenberg and Berthe Hirsch.
The couple had two daughters together: Bertha Helene and Margarete Helene.
Since 1935, the Mayer family has resided in Den Haag, in Gouda and in Amsterdam. Their last address per 20 August 1943 was Hofmeyrstraat 2 I…