The dpa news agency said Sonja Suder was sentenced to 3 and a half years in prison after her conviction today in the Frankfurt state court.
Suder was part of the radical Revolutionary Cells group that carried out two arson attacks on German companies in 1977, and a third in 1978 on the Heidelberg Castle.
Suder had fled to France in 1978 but was extradited to Germany in 2011 to face trial.