Police in the city of Bonn said the assault happened in a park on Wednesday afternoon. A police statement says the professor's companion reported it, but the officers who arrived knocked the professor to the ground and hit him in the face, initially mistaking the victim for the perpetrator.
Bonn Police Chief Ursula Brohl-Sowa met with the professor on Thursday to apologize for the officers' mistake.
Police say a male suspect was identified and temporarily detained. They said he was a 20-year-old already known to police.
Concern has been rising about a resurgence of open anti-Semitism in Germany.
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