Intolerance and conspiracy theories have haunted the margins of France's "yellow vest" movement since the first protests over fuel taxes roused the discontented middle of French society.
The men and women in fluorescent safety vests blocking traffic and intimidating shoppers on the famed Champs-Elysees Avenue vent a range of grievances against the government.
But over 11 weeks of yellow vest protests, views from the fringes have bubbled through the diffuse and leaderless movement and have been amplified: anti-Semitic rants about banking, a Holocaust survivor harassed on the subway, assaults on journalists, and claims the government concocted terrorist attacks or deadly accidents to divert attention from the demonstrations.
There has been scattered violence at the protests, with clashes between participants and riot police, and authorities worry that the extremists have taken over the center of the movement, risking a return to the darker episodes from France's past.
On Saturday in Paris, a man in a yellow vest turned toward a journalist filming at the sidelines of an otherwise quiet match, hurled a homophobic epithet and added: "You work for the Jews." No one in the march joined in, but neither did they contradict him.
In a more positive sign, a group of several hundred protesters forming a human chain in central Lyon inadvertently converged with a Holocaust commemoration that was planned separately by the city. After the boisterous protesters largely complied with a moment of silence for Holocaust victims, Deputy Mayor Jean-Dominique Durand, who organized the memorial, urged the group to "clean house" of any extremist views.
"It was an important moment to show that anti-Semitism has no place here," said yellow vest protester Thomas Rigaud, according to Europe 1 radio.
Marchers at one of the first yellow vest rallies in Paris in November held the French flag aloft while chanting "This is our home!" — a double-edged slogan that resonates with the far-right National Rally party, whose leader Marine Le Pen calls it a "cry of love" for France; critics see only anti-immigrant overtones.
In December, a group of marchers in Paris' bohemian Montmartre neighborhood proffered an anti-Semitic salute. They sang lyrics associated with Dieudonne M'bala M'bala, a French comedian convicted several times of racism and anti-Semitism. The hand gesture and song are both called the "quenelle," with the gesture mimicking an inverted Nazi salute and the song hinting at Zionist plots. Dieudonne describes them as anti-establishment symbols.
On that same day, men in yellow vests harassed an elderly Holocaust survivor on a subway train when she asked them to stop making the gesture, and one of them replied that the gas chambers that had killed her father never existed. A journalist who saw the exchange said no one took the woman's side. France's interior minister said the train operator was trying to identify the men, saying "whether hidden by a yellow vest or in the anonymity of Twitter, anti-Semitism must be fought with all strength."
Some of France's most notorious anti-Semitic personalities have been seen at the forefront of some of the Paris protests.
One of them, Herve Ryssen, appeared on the cover of the weekly Paris Match, facing police as he stood before the Arc de Triomphe. Ryssen has been convicted repeatedly of anti-Semitism and provoking acts of discrimination. He was convicted again last week for Holocaust denial, a crime in France for decades that harkens back to the country's history of surrendering French Jews to the occupying Nazis to be killed.
Government spokesman Benjamin Griveaux acknowledged that protests varied from town to town, but said last week that some were marked by "paramilitaries close to the extreme right." Among them were Victor Lenta, a former soldier who fought alongside pro-Russian separatist forces in Ukraine.
Maxime Nicolle, a YouTube personality who goes by the handle Fly Rider, and Eric Drouet, a trucker who was among the early yellow vest organizers, also have emerged as prominent voices.
The Jean Jaures Foundation, a think tank connected with the Socialist Party, studied online activity by Drouet and Nicolle, and said both are tacitly affiliated with France's far-right party.
It said Drouet shared anti-migrant videos and provided a Facebook platform for discuss plots involving Zionists, banks, and the media. The study said Nicolle had repeatedly liked videos linked with the party that lost to President Emmanuel Macron.
Nicolle has publicly expressed doubts about French authorities' account of a gunman killing five people near a Strasbourg Christmas market in December. The Islamic State group claimed responsibility for the attack, which derailed the next weekend's yellow vest protest. He, like others in the yellow vest movement, said he did not believe it was terrorism and mused that the government benefited from the timing.
"I don't trust anything I cannot see," he said.
Organizations that track racist and anti-Semitic incidents in France say more of both were reported in 2018, though they haven't finished compiling the data. SOS Racisme, a coalition of groups co-founded by French intellectual Bernard-Henri Levy, said it received 587 reports last year, compared with 508 in 2017. The government has not made its final figures public for the year.
"I would not say that the movement is anti-Semitic, but I say that these mass movements are always exploited by anti-Semites," said Francis Kalifat, president of CRIF.
That was a danger sign for France that the movement "will try to win in the streets what they lost in the vote," he said.
Conspiracy videos about the Rothschilds, a French Jewish banking family that frequently is at the center of global conspiracy theories, appear prominently on many of the yellow vest Facebook feeds. Macron — the chief target of the weekly protests because of policies seen as benefiting the wealthy — used to work for the family's investment bank.
The Jewish banker-as-scapegoat theme came up repeatedly in conversations with yellow vest marchers Saturday in Paris. Still, several peaceful marchers expressed concern about actions by the radical fringe. The grassroots movement is increasingly seeing divisions between its moderates and extremes.
To join two of the most popular Facebook groups for the yellow vests, members must agree to rules including being kind and courteous, and to not incite hatred or harass or insult other participants. On Saturday, at a meeting in northern France, there was little the about 100 delegations could agree upon except an affirmation that they were "neither racist, nor sexist, nor homophobe" — an apparent pushback against the recent allegations.
That hasn't stopped Dieudonne, on his 10-minute YouTube shows, from selling his own version of a yellow vest printed with a vulgar reference to Macron and the song heard on the steps of Montmartre. He said he has sold out of the vests, but has ordered another shipment.
Associated Press writer Angela Charlton contributed.