The European Court of Human Rights (ECHR) on Thursday found France guilty of unlawfully employing a controversial police tactic to encircle protesters during a 2010 demonstration.
The method, known as "kettling", consists of police cordoning off areas to contain groups of protesters in a small space -- sometimes for hours -- until in the police's view, they can no longer cause trouble.
Police used the tactic at a 2010 demonstration in Lyon, southeastern France, against pension reform under then-president Nicolas Sarkozy which sparked violent clashes between protesters at police in several French cities.
While acknowledging that there were good reasons to cordon off the city's Place Bellecour square to stop unrest spreading, the court also said there was no legal basis at the time for doing so.
France therefore violated two key provisions of the European human rights convention -- freedom of movement and freedom of assembly and association, it ruled.
"The court concluded that the police's use of the kettling technique had not, at the relevant time, been 'prescribed by law'", it said in a statement.
France's interior ministry has since issued national instructions for maintaining public order which make the kettling practice legal, the court said.
The plaintiffs' lawyer, Patrice Spinosi, called the verdict "a victory" because it showed that kettling was "illicit" at the time.
He said the subsequently established legal basis for the practice was "not a blank cheque for police", who could still be challenged if they used the tactic "indiscriminately".
The case was filed by around a dozen participants at the demonstration on October 21, 2010, one of a series of sometimes violent protests against the pensions reform bill.
Up to 600 people gathered at Place Bellecour for the demonstration, for which the authorities had been given notice.
Two hours into the protest, police put in place kettling measures which were called off only more than three hours later, making it impossible for people inside the cordon to join the demonstration.
A number of demonstrators filed a complaint with the French judiciary, which threw out their case.
They then took their complaint to the ECHR in December 2021, saying the kettling measure had violated their freedom of movement in a way that was not regulated by law.
Kettling, also known as "corralling", is often criticised for indiscriminately affecting both protesters and non-demonstrating bystanders who happen to be in the same location, often depriving them of access to water, food and toilets for hours.
It is in widespread use across the world and has been challenged legally in several cases, sometimes successfully.
