Emma Zimmer was the oldest female guard to serve at Auschwitz and became notorious for her brutality toward prisoners. Beginning her concentration camp career at Lichtenburg in 1937, she later served at Ravensbrück, where survivors remembered her vicious beatings and cruel punishments.

As a senior warden, Zimmer participated in selecting prisoners who were sent to the Bernburg Euthanasia Centre to be murdered. In 1942, aged 54, she was transferred to Auschwitz-Birkenau, where survivors again recalled her threats and brutality. By the end of 1943, her camp career was over, with alcohol consumption cited as one possible factor.

After the Second World War, Zimmer was arrested and tried during the Seventh Ravensbrück Trial for mistreating prisoners and participating in selections for the gas chamber.