The two groups, 30 Muslims and 60 Yazidi, set upon each other with their fists and feet and any objects they found to hand in the Neuenhäusen area of the city, the Cellesche Zeitung reported.
More than 50 police officers were deployed to separate the two groups after they were alerted to the running battle at 5.30pm, a police spokesman told The Local. No-one beyond the two groups was involved or hurt in the fight.
Police said that they would continue keeping an eye on the area to ward off further confrontations.
No-one was arrested, but police are investigating cases of grievous bodily harm and serious breach of the peace.
Investigators have visited the hospital to speak with the injured and identify their assailants.
Police suggested that the conflict in Syria and Iraq might have sparked off the street battle.
The Yazidi people, non-Muslim Kurds from northern Iraq, have been especially persecuted by successive Iraqi governments and most recently by Isis. Around 60,000 live in Germany.
A confrontation between Muslims and Yazidi over the Iraq and Syria conflict led to violence which had to be contained by a massive police deployment in Herford, North Rhine-Westphalia, in early August.
The street fight came on the same day as Kurds across Europe demonstrated to draw attention to the dire situation on the Turkish-Syrian border.
In Germany, demonstrators broke into the studios of broadcasters Westdeutsche Rundfunk in Düsseldorf and Deutsche Welle in Bonn.
Around 600 Kurds gathered in Berlin on Monday night and marched from the Brandenburg Gate to Alexanderplatz.
A police spokesman told The Local it was a peaceful demonstration which didn't require a police deployment, although some participants displayed symbols of the Kurdistan Workers' Party (PKK), which is banned in Germany.
Demonstrations were also reported in Hamburg, Dortmund, Münster and Essen.
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