About 1,300 police officers were dispatched simultaneously at 21:00 local time (2000 GMT) in Bochum, Duisburg, Essen, Recklinghausen, Dortmund and Gelsenkirchen.
Tax authorities, customs and city administrators also participated the crackdown.
It was said to be the biggest operation in Germany against the criminal gangs to show lawless areas were not tolerated. Some Shisha bars and local facilities were searched, local media Focus reported, citing sources from the interior ministry.
The initial results of the operation will be disclosed on Sunday.
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