Police officers in three cities in North Rhine-Westphalia and in Berlin searched buildings on suspicion of insurance fraud and money laundering.
According to the police and prosecutors, the investigations are aimed at six suspects, some of whom are attributed to a large family clan.
At the same time, police officers appeared at several apartments and commercial properties in Duisburg, Essen, Düsseldorf and Berlin on Wednesday, said a spokesman for the Duisburg police.
The suspects are two women and four men between the ages of 19 and 61.
Damage of around 200,000 euros
According to this, an insurance company with alleged water damage to a building in Berlin is said to have been cheated in the corresponding amount, as a spokeswoman for the Duisburg public prosecutor said on request.
The damage is said to be around 200,000 euros.
"We're also trying to secure assets," she said.
There were no arrests.
A Duisburg police unit for organized crime is in charge of investigating the case.
The public prosecutor's offices in Duisburg and Düsseldorf, police forces from Düsseldorf and Essen as well as the State Criminal Police Office in Berlin and the main customs office in Düsseldorf are involved in the operation.
It was initially unclear whether and which evidence or assets were seized.
The authorities did not want to reveal how many officers were deployed.
The Lebanese clan is said to be one of the largest in North Rhine-Westphalia.