Thousands of people rallied in central Paris on Sunday in a defiant show of solidarity with a teacher beheaded for showing pupils cartoons of the Prophet Mohammed.
Demonstrators on the Place de la Republique held aloft posters declaring: "No to totalitarianism of thought" and "I am a teacher" in memory of murdered colleague Samuel Paty.
"You do not scare us. We are not afraid. You will not divide us. We are France!" tweeted Prime Minister Jean Castex, who was among those gathered at the historic protest spot.
Mr Castex was accompanied by Education Minister Jean-Michel Blanquer, Paris mayor Anne Hidalgo and junior interior minister Marlene Schiappa who said she was there "in support of teachers, of secularism, of freedom of expression".
Some in the crowd chanted "I am Samuel", echoing the "I am Charlie" cry that travelled around the world after Islamist gunmen killed 12 people at the Charlie Hebdo satirical magazine in 2015 for publishing caricatures of the Islamic prophet.Between bursts of applause, others recited: "Freedom of expression, freedom to teach."
People gather during a demonstration on Sunday, 18 October, 2020 in Paris. Source: AP
"I am here as a teacher, as a mother, as a Frenchwoman and as a republican," said participant Virginie.
The Charlie Hebdo attack in 2015 unleashed a wave of Islamist violence and forced France into a national discussion about Islam's place in a secular society.
After the massacre at the magazine, some 1.5 million people gathered on the same Place de la Republique in support of freedom of expression.
'Things have to change'
Local authorities said around 6,000 people gathered in Lyon in eastern France on Sunday.
"The entire educational community is affected, and beyond it society as a whole," teachers union representative Bernard Deswarte said in Toulouse, where around 5,000 were estimated to have gathered.
Hundreds more assembled in Nice on the south coast, where a man rammed a truck into a crowd on the 14th of July national holiday in 2016, killing 86 people.
"Everyone is in danger today," said student Valentine Mule, 18, attending the Nice rally.
"Things have to change."
Demonstrations were also planned for other cities.
Mr Paty was brutally murdered on his way home from the school where he taught in a suburb northwest of Paris on Friday afternoon.
On Saturday, anti-terror prosecutor Jean-Francois Ricard said Mr Paty had been the target of online threats for showing the cartoons to his civics class.
Depictions of the prophet are widely regarded as taboo in Islam.
A photo of the teacher and a message confessing to his murder was found on the mobile phone of his killer, 18-year-old Chechen Abdullakh Anzorov, who was shot dead by police.
Witnesses said the suspect was spotted at the school on Friday asking pupils where he could find Mr Paty.
Online campaign
The father of one schoolgirl had launched an online call for "mobilisation" against the teacher and had sought his dismissal from the school.
The girl's father and a known Islamist militant are among those arrested, along with four members of Mr Anzorov's family.
An 11th person was taken into custody on Sunday, a judicial source said, without providing details.The aggrieved father had named Mr Paty and given the school's address in a social media post just days before the beheading which President Emmanuel Macron has labelled an Islamist terror attack.
Thousands gathered to demonstrate against the killing of a French school teacher in a terrorist act last week in Paris. Source: AP
Mr Ricard did not say if the assailant had any links to the school or had acted independently in response to the online campaign.
The Russian embassy in Paris said Anzorov's family arrived in France from Chechnya when he was six to seek asylum.
Locals in the Normandy town of Evreux where the attacker lived described him as low key, saying he got into fights as a child but calmed down as he became increasingly religious in recent years.
Friday's attack was the second of its kind since a trial started last month over the Charlie Hebdo killings.
The magazine republished the controversial cartoons in the run-up to the trial, and last month a young Pakistani man wounded two people with a meat cleaver outside Charlie Hebdo's former office.
A protestor in Paris carries a sign stating: 'I am Samuel' during a demonstration following the brutal killing of French school teacher Samuel Paty. Source: AAP
'Doing his job'
On Saturday, hundreds of pupils, teachers, parents and well-wishers flocked to Mr Paty's school to lay white roses.
"For the first time, a teacher was attacked for what he teaches," said a colleague from a neighbouring town who gave only his first name, Lionel.
According to his school, Mr Paty had given Muslim children the option to leave the classroom before he showed the cartoons, saying he did not want their feelings hurt.
And Kamel Kabtane, rector of the mosque of Lyon and a senior Muslim figure, told AFP on Sunday that Mr Paty was merely been "doing his job" and had been "respectful" in doing so.
A national tribute is to be held for Mr Paty on Wednesday.