After a fight between members of an extended family, the police arrested a woman and six men on Friday night.
A shot was fired during the dispute, which broke the window of a child's room.
In addition, those involved are said to have attacked each other with a hammer, baseball bat and pepper spray.
Bremen - Two men suffered injuries, the police said.
It will be determined because of various crimes of bodily harm, trespassing and violations of the gun law.
The police searched homes and secured evidence.
The head of the Bremen State Criminal Police Office, Jürgen Osmers, assigned several participants in the brawl to clan crime and emphasized: "The Bremen police do not tolerate any criminal acts within or from so-called clans or large families." Dpa