French police have arrested nearly 30 people suspected of financing extremists with cryptocurrency in Syria.
Prosecutors allege the terrorism-financing network supplied coupons to extremist contacts in Syria that were then credited to Bitcoin accounts.
The move away from handling cash marks a new, more sophisticated method for the foreign financing of terror cells, police said in a statement.
A total of 29 people were arrested in the sting.
"Constant surveillance of these networks prompted terrorist organisations to seek more opacity by using cryptocurrencies such as Bitcoin," the police statement said.
Two French extremists, identified as Mesut S and Walid F, both 25, are believed to be the architects of the network, working from north eastern Syria, the prosecutors said.
The ringleaders are suspected members of the Hayat Tahrir Al Sham organisation, an Al Qaeda affiliate.
Both men were sentenced to 10 years in prison in their absence in 2016, and are currently the target of an international arrest warrant.
Their accomplices were caught after purchasing coupons worth 10 to 150 euros ($12 to $176) each on many occasions over recent months in several locations in France.
Such coupons are available at licensed tobacco outlets known as Tabacs - of which there are about 24,000 in France - that also offer various small payments services, such as cash card top-ups and money coupons, without requiring proof of identity.