France, Nov. 26 -- The inquiry centres on SOS Donbass, officially Sud-Ouest Solidarite Donbass, which presents itself as a humanitarian organisation. Prosecutors said the group is suspected of serving as a cover for covert activity.

Investigators first turned to Anna M, a 40-year-old dual national who founded the association.

Domestic intelligence services identified actions they said could harm France's fundamental interests. An investigation was opened on 13 March after she was suspected of approaching senior staff at French companies to obtain economic information.

Investigators later linked the probe to pro-Russia posters placed on the Arc de Triomphe.

EU to investigate Hungarian spy ring that targeted Brussels institutions Poster...