The year-long operation leading to the arrests focused on the movement of money through clandestine banking services run by ethnic Chinese individuals.
In a joint operation, police in Italy and Spain have arrested 58 people on suspicion of international drug trafficking, money laundering, and fraud.
Some 400 officers using sniffer dogs participated in the police operation, carrying out a total of 96 searches in Italy, Switzerland, and Spain.
In Italy, the arrests took place in Milan, Turin, Rome, and Catania in Sicily.
Agents seized assets worth €129 million.
The year-long investigation had focused on the suspicious movement of money through clandestine banking services run by ethnic Chinese.
It is estimated that the network supplied around 30 million tonnes of hashish and marijuana.