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 Elysée, 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.
Earlier 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.
Khéops Lara, Mr. Drouet’s lawyer, said in a statement published on social media on Thursday that his client had been “arbitrarily arrested” for a gathering that did not qualify as the kind of demonstration that requires prior authorization.
After he lit candles on the Place de la Concorde in memory of the movement’s wounded, he “wanted to gather with some close relations and friends in a private location, most notably a restaurant, to talk and exchange,” Mr. Khéops said, “without violence, without hatred.”
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 4 hours in custody to spoil their image, I’ll go.”