The operation involved Europol, Dutch police and the FBI and also led to the arrests of two major suppliers of illegal narcotics in the United States, they said.
The illicit “Wall Street Market” site enabled trade in cocaine, heroin, cannabis and amphetamines as well as stolen data, fake documents and malicious software.
The encrypted platform had more than one million customer accounts, over 5,000 registered sellers and more than 60,000 sales offers, Frankfurt prosecutors said.
The site was accessed through the encrypted Tor network to shield customers from detection and transactions were made with crypto currencies Bitcoin and Monero.
The operators allegedly received commissions of two to six percent of the sales value.
German police had on April 23rd and 24th arrested the three German suspects aged 22 to 31 in the states of Hesse, Baden-Württemberg and North Rhine-Westphalia.
They also seized servers, over 550,000 euros (about $600,000) in cash, and hundreds of Bitcoin and Monero, as well as several vehicles and a gun.
The police operation started after Finnish authorities shut down the illegal Tor trade site Silkkitie (Valhalla) earlier this year, said Europol.
This had led some Finnish narcotics traders to move to the Wall Street Market.
In the United States, an investigation in Los Angeles led to the arrests of two of the highest-selling suppliers of narcotics, and the seizure of illegal weapons as well as millions of dollars in cash, said German authorities.