A video of French students being forced to kneel with their hands behind their heads by riot police has sparked outrage on social media.

The students in the video, taken on earlier this week, were part of a protest in the western Paris suburb of Mantes-la-Jolie against proposed overhauls to national exams.

Demonstrations against the exam proposals have slowly spread around the country, at the same time as France has been shaken by the “yellow vest” protests, which started as opposition to a planned increase in France’s fuel tax.

Jacques Toubon, France’s ombudsman for human rights, said he had opened an investigation into the treatment of the students on Friday.

Local officials defended their actions, saying they were trying to prevent violence like that sparked by the yellow vest protests, in which four people have died and 700 have been wounded.

The roundup of the students in this manner was called “simply intolerable” by Cécile Duflot, a former housing minister and now the director general of Oxfam in France. The incident was also condemned by other human rights advocates and politicians.

The initial footage of the incident, shared on Twitter by the Violences Policières group, had more than two million views less than a day after it was posted.

More than 140 students were collectively arrested on Thursday after protests at two high schools in the area, according to police officials speaking to newspaper Le Monde.

Tensions had been brewing for days at Saint-Exupéry and Jean-Rostand high schools. On Tuesday, rubbish bins were set on fire and rocks thrown at police, according to Le Monde. Police responded with tear gas.

Clashes at the Paris fuel protests: in pictures Show all 29 1 /29 Clashes at the Paris fuel protests: in pictures Clashes at the Paris fuel protests: in pictures Water cannons are turned on the protesters Reuters Clashes at the Paris fuel protests: in pictures Riot police detain protesters EPA Clashes at the Paris fuel protests: in pictures A car is set alight in the protests AFP/Getty Clashes at the Paris fuel protests: in pictures The Arc de Triomphe is graffitied with the slogan: 'he yellow vests will triumph' Reuters Clashes at the Paris fuel protests: in pictures Protesters barricade themselves on the Champs Elysees as police line the streets Reuters Clashes at the Paris fuel protests: in pictures A protester fires at police with a slingshot AFP/Getty Clashes at the Paris fuel protests: in pictures A protester holds up a sign that reads 'your Europe ruins us' Reuters Clashes at the Paris fuel protests: in pictures A protester gestures amidst burning cars EPA Clashes at the Paris fuel protests: in pictures Protesters walk amidst tear gas near the Arc de Triomphe Reuters Clashes at the Paris fuel protests: in pictures A protester runs amidst tear gas Reuters Clashes at the Paris fuel protests: in pictures Protesters on the Champs Elysees amidst tear gas AFP/Getty Clashes at the Paris fuel protests: in pictures Protesters in yellow vests gather outside the town hall in Bordeaux EPA Clashes at the Paris fuel protests: in pictures Protesters gather on the Champs Elysees after the police deploy tear gas AFP/Getty Clashes at the Paris fuel protests: in pictures Protesters stand by the Tomb of the Unknown Soldier in Paris AFP/Getty Clashes at the Paris fuel protests: in pictures A protester waves a French flag Reuters Clashes at the Paris fuel protests: in pictures Riot police take formation AFP/Getty Clashes at the Paris fuel protests: in pictures A general view of the Champs Elysees in Paris today as protesters clash with police Reuters Clashes at the Paris fuel protests: in pictures A protester wears a jacket reading 'Macron, thief, lier, crook, go away, the people banish you' AP Clashes at the Paris fuel protests: in pictures Protesters gather on the Champs Elysees AFP/Getty Clashes at the Paris fuel protests: in pictures Protesters hold a French flag by a burning barricade AFP/Getty Clashes at the Paris fuel protests: in pictures Protesters gather by a fire AFP/Getty Clashes at the Paris fuel protests: in pictures Water cannons are turned on the protesters Reuters Clashes at the Paris fuel protests: in pictures A protester wears an adapted yellow vest reading 'Macron's cemetery: here lies your buying power' AFP/Getty Clashes at the Paris fuel protests: in pictures Protesters gather by a burning car AFP/Getty Clashes at the Paris fuel protests: in pictures Riot police advance through tear gas followed closely by their water cannon EPA Clashes at the Paris fuel protests: in pictures Tear gas is deployed to deter the protesters Reuters Clashes at the Paris fuel protests: in pictures A protester waves a French flag amidst tear gas AP Clashes at the Paris fuel protests: in pictures Protesters walk amidst tear gas by the Arc de Triomphe Reuters Clashes at the Paris fuel protests: in pictures A protester holds a sign asking for the reintroduction of ISF (an old French tax on wealth) AFP/Getty

Left-wing politician and former presidential candidate Benoit Hamon described the scene as “chilling”, while Eric Coquerel, a far-left member of Parliament said the violence was "unacceptable and humiliating.”

Florian Philippot, a far-right politician, said: “Re-establish order, yes. Those useless and shocking methods, no. Not in France.”

Jean-Michel Blanquer, the education minister, said that while the images were shocking, it was important to understand the environment in which the arrests took place.

“When I saw these images myself, I was obviously shocked,” he told France Inter radio. “We must find out what happened before, the context in which this unfolded.”

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Some officials defended police, pointing to the mounting tensions between the students and police over the past few days. A local prosecutor, Vincent Descloud, told Le Monde that security forces “had to opt for a law enforcement solution.”

On Friday, dozens of students and teachers showed their support for those arrested, reproducing their kneeling pose in Paris and in several other cities. A large group gathered in Place de la République in Paris in solidarity with the students.