Jakob Lindenthal was attached to the Physics Department of the IIT Madras.
Senior Congress P Chidambaram on Tuesday said the incident involving a German student participating in the anti-Citizenship Act protest was a reminder of the dark chapter in world history.
"The German is reminding us of a dark chapter in the world's history so that we may not repeat that in India. The student deserves our gratitude. Where is the Director of IIT? Where is the Chairman? Let us hear from both of them.
"Where are the other students of IIT? They should protest the reported expulsion of a German student," he asked on Twitter.
A German student, who took part in anti-CAA protests last week, has left India after Bureau of Immigration authorities asked him to leave since his participation in demonstrations over domestic issues allegedly violated visa regulations.
Jakob Lindenthal, who was here on an exchange programme, was attached to the Physics Department of the IIT Madras and he left the country on Monday night, sources at the institute said.
Holding a placard that had an indirect reference to the Nazi persecution of Jews in Germany between 1933-45 during Hitler's regime, he had told co-participants at a protest that small measures against Jews had not attracted much attention initially.