French authorities have detained three people, including two Russian nationals, and placed a fourth under judicial supervision as part of a probe into spying for a foreign nation, Paris prosecutors said on Wednesday.
French news agency AFP reported that the people had been arrested for spying for Russia and promoting Russian war propaganda.
The investigation focuses on SOS Donbass, a French-Russian association suspected of spreading pro-Moscow propaganda and seeking sensitive economic information.
SOS Donbass presents itself as a humanitarian organization, which offers aid to people in the eastern Donbas region of Ukraine, partially under Moscow's control.
Those arrested include the group's leader, a 40-year-old woman born in Russia, a 40-year-old Russian man, and a 63-year-old Frenchman. A fourth suspect, 58, was placed under supervision and asked to report to the police station once a week.
In France, the crime of "collusion with a foreign power" is punishable by 10 years in jail.
The arrests come as Europe steps up vigilance against suspected Russian influence operations amid the war in Ukraine.