The police said numerous officers were patrolling the Hauptwache plaza and the nearby Zeil shopping street on Saturday night when they were pelted with rocks, bottles and eggs "without an obvious reason."
Some 500 to 800 people came together spontaneously to attack the officers, "without following corona rules." Nine people were arrested but eight of them were released due to the lack of evidence. A 17-year-old remains in custody.
This is the second straight night of attacks on police in Germany's main financial hub following Wednesday's announcement by Chancellor Angela Merkel that the country would go back into a partial lockdown for a month starting Monday, in a bid to limit the spread of the virus.