The lecture by Justus Wertmuller, a pro-Israel author, in July was sponsored by the German-Israel Friendship Society, the Jerusalem Post reported. After the University of Rostock refused to give the group a room, the lecture was held off campus with no problems.
Ulrich Vetter, a university spokesman, said the school has no legal obligation to provide space to outside speakers.
"The domestic intelligence agency shared the fear of the university management and recommended to the rector that the event not be permitted in the room at the university," he said.
An employee of the Mecklenburg-Western Pomerania intelligence agency told the Post the decision was the university's, although officials sought advice from the agency. The agency has no information suggesting Wertmuller is dangerous, the employee added.
Alex Feuerherdt, a German journalist who writes about attitudes towards Israel and German anti-semitism, said the intelligence agency has "criminalized de facto engagement for Israel and this is a particularly huge scandal in light of German history."