She and her husband in Syria are said to have held a Yezidi girl and two Yezidi women as slaves, according to the indictment from the federal public prosecutor general.
Ten trial days have been set aside for the case, according to the court, with a verdict possible on November 16.
According to the indictment, former student Sarah O travelled to Syria in 2013 to join Islamic State.
In 2014, she married the Islamic State fighter Ismail S, also from Germany, according to Islamic law.
The two are believed to have conducted security and police services for Islamic State together.
According to the indictment, the Yezidis had to look after the house and the couple's children as slaves.
When the situation became tight for Islamic State in Syria, Sarah O fled to Turkey, from where she was deported to Germany.
In September 2018, the young woman and her three children landed at Dusseldorf Airport and she was arrested.
Her in-laws are also charged along with the young woman. They are accused of supporting their son and his brother in supplying Islamic State.
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