Police in France and Belgium said Friday they had smashed a criminal ring that used fake court summonses accusing people of watching child pornography to extort at least €3.5 million.

The phishing scam involved false emails from police, judges or institutions such as Europol threatening victims with prosecution unless they paid a "fine".

Police said they arrested 18 people in France and one in Belgium in an operation on Monday, with all but three of the suspects ordered to appear in court on fraud charges.

One of the victims - who had been stung twice by the crooks - committed suicide, and six others may have also potentially killed themselves, police said.

"We thought that the fraud was being run by one central structure," said Colonel Thomas Andreu, head of one of the special French police units. "However, it turned out to be several little teams which were not linked." 

The sums extracted from the victims ranged from less than €5,000 to up to €200,000, he told AFP.

The scam began at the start of 2021, leading the cybercrime section of the Paris prosecutor's office to open an investigation. 

By June 2022 some 400 complaints relating to the scam had been made to authorities.

Commissioner Christophe Durand, of the French OCLCTIC anti-cybercrime unit, said the "victims had suffered real distress".

Some of the money extorted from the men - who were aged on average around 60 - was spent in France, but most was sent to the Ivory Coast and other African countries. 

The man who was hit twice was first made to pay €5,978 before the criminals asked him for a further €7,480.  

"Feeling powerless and trapped, he took his own life," the police said.

The suspects are aged between 20 and 50.