In the Osnabrück district, the police broke up a party in a hut.
The officials had found six heavily drunk men between the ages of 20 and 44 after a notice, the police said on Sunday.
The men had shown themselves to be uncooperative and aggressive.
According to the information, a party guest should be taken to the guard to determine their identity.
But he refused.
When he was to be led to the patrol car, four men attacked the police, it was said.
The officers used pepper spray and detained all the celebrants.
A 21-year-old injured a 29-year-old policeman in the knee so badly that he was unable to work.
The police are investigating violations of the regulations to contain the corona pandemic.
Icon: The mirror
kha / dpa