One of the leaders of the "yellow vest" anti-government demonstrations, Eric Drouet, was detained by French police and placed in custody on Wednesday for organizing a central Paris protest without declaring it, according to a source at the prosecutors office.
Drouet — who already faces a trial for carrying a weapon — was held while heading for the Champs-Elysees, according to a police source.
A few dozen demonstrators had gathered outside a McDonalds near France's famous Arc de Triomphe war monument and had been waiting for Drouet to arrive early Wednesday evening.
"Yellow vest" demonstrations — so-called after the high-visibility jackets they wear — began in rural France in November over fuel taxes and ballooned into a wider revolt against President Emmanuel Macron's pro-business policies, which they view as skewed towards the rich.
The protesters have repeatedly clashed with police in Paris and other big French cities, plunging Macron's presidency into crisis.
Drouet was first arrested last month. He face trial on June 5 for "carrying a prohibited category D weapon", a judicial source told AFP.
Radical leftist leader Jean-Luc Melenchon, a fierce critic of Macron, tweeted: "Again Eric Drouet arrested, why? Abuse of power. A politicized police targeting and harassing the leaders of the yellow vest movement."
After weeks of violence, Macron eventually scrapped the unpopular fuel tax rise in response to the protests and promised extra cash for minimum wage earners and tax cuts for pensioners.
Although the number of protesters taking part in the demonstrations has since dwindled, they have continued.