PARIS — The French police have arrested a prominent leader of the Yellow Vest movement for a second time, in a clear sign that the government is following through on a pledge to crack down on the protests that have shaken France for much of the past six weeks.
Éric Drouet, a 33-year-old truck driver from the Paris exurbs who was one of the original organizers of the movement, was arrested Wednesday night in Paris for what the authorities said was “organizing an undeclared demonstration.” On Thursday, he was released pending a trial.
“We’ve got to shock public opinion,” Mr. Drouet said in a video on Facebook before going to the Place de le Concorde on Wednesday and placing candles for the movement’s wounded. He called for “action” on the Champs-Élysées, where several dozen Yellow Vests were waiting for him that evening outside a McDonald’s restaurant.
Instead, shortly after 9 p.m., Mr. Drouet was hustled into a police van by riot police officers.
French law requires the organizers of street demonstrations to inform the local authorities about their plans. Violations can bring six months in jail and a fine of 7,500 euros, about $8,500.
After his release on Thursday, Mr. Drouet told reporters that he had been unfairly targeted for “political” reasons and denied that he had called on anyone to demonstrate. He noted that none of those gathered had been wearing yellow vests.
“It was nothing like a demonstration,” he said. “It was a rendezvous at the restaurant.”
Khéops Lara, Mr. Drouet’s lawyer, said in a statement that his client had been “arbitrarily arrested” and that the gathering did not qualify as the kind of demonstration that requires prior authorization.
The French authorities dismissed Mr. Drouet’s claim that he had merely been meeting a group for a restaurant outing.
Prime Minister Édouard Philippe, asked on Thursday by reporters during a trip north of Paris if there were “political police” in France, replied, “In no way.” He expressed support for the French police and judiciary.
The arrest of Mr. Drouet, who had previously been detained and accused of carrying a wooden club at a demonstration on Dec. 22, signaled the new, harsher line taken by a government that has been knocked off balance by several weekends of often violent street demonstrations.
Mr. Drouet will be tried in February on charges of “organizing a demonstration without authorization,” both on Wednesday and on Dec. 22, the Paris prosecutor’s office said in a statement on Thursday. He will be tried in June over the club accusation.
The crackdown has been evident not just in tough police tactics, including the abundant use of tear gas and hundreds of pre-emptive arrests, but in the tone of President Emmanuel Macron’s most recent national address, on New Year’s Eve.
Mr. Macron was sharply critical in that speech of what he called the “hateful mob” aspect of the Yellow Vest movement, and issued a stern summons to respect “republican order.” That idea was echoed in his government’s defense on Thursday of Mr. Drouet’s arrest.
“He wasn’t respectful of the rule of law,” said the economy minister, Bruno Le Maire.
The tough new approach — and especially the arrest of Mr. Drouet — risks backfiring amid a popular revolt over economic woes and the answers offered by a government widely seen as distant and insensitive. Although the movement is clearly slowing down, the people taking to the streets remain mostly dissatisfied, despite Mr. Macron’s attempts to placate them.
Yellow Vest members interviewed on French television Thursday were sharply critical of the government, as were members of the political opposition. The far right and the far left in France have been engaged in a quiet war to win over the Yellow Vests, and the leaders of both denounced the arrest of Mr. Drouet.
The far left leader Jean-Luc Mélenchon called it an “abuse of power” and said that politically driven police were “targeting and harassing the leaders of the Yellow Vests.” On the far right, Marine Le Pen said on Twitter that there was “systematic violation of the political rights” of Mr. Macron’s opponents.
In a movement often described as amorphous, Mr. Drouet has stood out, frequently appearing on television and shocking French public opinion by declaring his readiness to “go inside” the Élysée were he to reach the presidential palace in a demonstration.
He created the original Facebook page calling for a national demonstration against a gas tax increase in November, and his calls to protest and his analyses of the movement — often live-streamed on Facebook from the cab of his truck — are popular among many Yellow Vests.
“I am not a representative of the Yellow Vests,” Mr. Drouet told reporters on Thursday — a common line from prominent members of the movement, who see themselves not as leaders of the protesters but as mere amplifiers of their demands. “With our without me, it will continue.”
This week, Mr. Mélenchon wrote of his “fascination” with Mr. Drouet on his blog, comparing him to a figure of the French Revolution, Jean-Baptiste Drouet, who stopped Louis XVI from fleeing France at the village of Varenne in June 1791.
Some French media outlets raised the possibility that Mr. Drouet had laid a trap for the authorities by taunting them with the intention of provoking his arrest.
“Imagine: I am checked by police, they take me in,” he said during a live stream on Facebook last month. “It will backfire on them. If I have to spend four hours in custody to spoil their image, I’ll go.”