For the past two months, Sergei Lenta wakes every Saturday and preps himself to fight for what he considers a deeply righteous cause. He dons a thick coat to cope with the bitter winter weather, a red military-style beret, a white armband, and a yellow reflective safety vest and heads to the center of Paris to call for the overthrow of French Republic.

Lenta is part of the French protest that started in November as a collective outcry against higher taxes and declining social benefits. But the 29 year old is not like thousands of fellow citizens who have taken to the streets. Lenta is an ideological warrior who fought with Russian-backed paramilitaries in the eastern Ukrainian province of Donbas before bringing his militant politics back home.

“We must end the Republic and democracy,” said Lenta at a weekly demonstration in late February.

The Yellow Vest movement has revealed the deep-seated fractures of French society and mistrust of politicians like President Emmanuel Macron to fix economic problems. At the same time, the movement has become a new battleground of ideas — and possible recruiting ground for fringe Kremlin-linked groups to take advantage of the social disorder for their own ends.