They are charged with spying on Sikh opposition and suspected Kashmiri separatist groups and passing on the information to India's external intelligence agency, the Research and Analysis Wing.
The trial of two Indian citizens accused of spying on Kashmiri and Sikh groups in Germany and sharing information with Indian intelligence agents began on Thursday at the Higher Regional Court in Frankfurt.
Manmohan S., 50, and his wife, 51-year-old Kanwal Jit K., were charged with foreign secret service agent activity in Germany.
Starting in January 2015, Manmohanis accused of obtaining information on Kashmiri separatist and Sikh groups operating in Germany and passing it on officials of India's external intelligence agency, the Research and Analysis Wing (RAW), posted at the Indian Consulate in Frankfurt.
From July 2017, his wife Kanwal Jit is also suspected of taking part in the intelligence gathering.
In return for their service, the couple reportedly received a total of €7,200 ($7,974) from RAW.
While the trial begins on Thursday, further hearings are scheduled up until December 12.
If convicted, the couple may be sentenced to up to 10 years in prison.