German engineer and socialite, notable as the younger brother of Leni Riefenstahl, with whom he had a very close and somewhat dependent relationship. Heinz and Leni Riefenstahl were known in the Berlin high society of the 1930s as das schöne Geschwisterpaar (“the beautiful siblings”), appearing together on various public occasions.
Heinz attended the premieres of his sister’s films as her male companion, including the premiere of the Nazi party film Triumph des Willens (“Triumph of the Will”) on 28 March 1935 in front of more than 2,000 spectators, including the most prominent Nazis. The bon vivant Heinz Riefenstahl and his famous sister maintained close contact with Nazi celebrities and military and government officials, including in particular the architect and later Reich Minister, Albert Speer.
In 1935, Heinz Riefenstahl married the eight-years-younger Ilse Margarete Rehtmeyer, and during their seven-year marriage they had two children, Eckart and Uta. After repeated breaches of faith by Heinz Riefenstahl and at the instigation of his sister Leni, they divorced on 9 December 1942. Rehtmeyer had always shared a strange kind of rivalry with his sister Leni, who resented Ilse. During the divorce case, custody of the two children was awarded to their father; Rehtmeyer had tried to commit suicide upon learning of her husband’s infidelities.
Leni Riefenstahl felt responsible for her younger brother Heinz and at the same time tried to ensure and increase his professional success. She found him clients and assignments through her own professional and social contacts, including those in the Nazi party.
On 9 December 1935, Heinz and Leni Riefenstahl founded the Olympia-film G.m.b.H. based in Berlin, with Heinz holding a ten percent stake.
In contrast to his sister, Heinz Riefenstahl actively helped when asked by a friend of Jewish descent for help.
Heinz Riefenstahl was drafted in May 1943 and sent to the Eastern Front. He was accused of “racial defilement” because of his (extramarital) relationship with a woman of Jewish descent.
Heinz Riefenstahl died on 20 July 1944, aged 38, while serving as a tank grenadier in the Soviet Union. Adolf Hitler sent his consolations by telegram. For the rest of her life Leni Riefenstahl considered herself responsible in part for the death of her beloved brother, because she had neglected to ask Hitler to recall him from the front. In his will, Heinz Riefenstahl gave his sister custody of his two children.

Link to Wikipedia biography (German)