Francois Molins, a major anti-terror prosecutor in France, said Thursday that the country's intelligence had distinguished 416 French sponsors sending money to Daesh to finance their terrorist activities, France 24 reported.
They also managed to identify 320 fundraisers, mostly from Turkey and Libya, who were responsible for money transfers, Molins argued.
The statement came as a two-day conference on dealing with terrorism financing kicked off on Wednesday at the Organization for Economic Cooperation and Development (OECD).
A French presidential official who held a speech during a press briefing ahead of the event said that Daesh' annual revenues reached almost one billion dollars in 2014-2016.
At the same time, the Europe 1 radio broadcaster reported that Daesh' leadership could possess about 3 billion euros (over $3.6 billion) as a result of the exploitation of formerly occupied territories in Iraq and Syria.
Daesh has claimed responsibility for a series attacks in Europe over the last few years, with coordinated terrorist attacks in November 2015 in Paris being the deadliest.
In the attacks, gunmen and suicide bombers carried out separate attacks at several sites, almost simultaneously: outside an ongoing France-Germany football match at the Stade de France stadium in the suburb of Saint-Denis; the Bataclan concert hall and Paris cafes, leaving a total of 130 people dead and some 368 injured.
Another attack took place on July 14, 2016 in Nice, when a 19-ton cargo truck drove into a crowd of people who were celebrating Bastille Day on the Promenade des Anglais in Nice. It claimed the lives of 86 people and injured 434.