A man is lifted up and taken to police lines after being beaten in clashes between protesters supporting the Black Lives Matter movement and opponents in central London on Saturday, in the aftermath of George Floyd's death in the US. Photo: AFP

Thousands marched in cities around the world for a second week of rallies Saturday to support the US Black Lives Matter movement, but also to highlight racism and police brutality in their own countries.

There were rallies in cities across Europe, with thousands demonstrating in several French cities, and clashes breaking out in Paris and Lyon.

Police arrested several far-right demonstrators in London after violence when they challenged people supporting racial quality there, with Prime Minister Boris Johnson denouncing their "racist thuggery."

The weeks of historic demonstrations have been ignited by the May 25 killing of African-American George Floyd by a police officer - the latest in a long line of unarmed black men being killed by white law enforcement in the US.

His agonizing death as the officer knelt on his neck was filmed by bystanders and swiftly went viral, triggering fury first in the US and then around the world.

The mass unrest has forced an unprecedented global conversation on the legacy of slavery, European colonialism and white violence against people of color, as well as the militarization of police in America.

Police stopped protesters in Paris on Saturday from marching through the capital, firing tear gas after some demonstrators pelted them with projectiles.

In the southeast city of Lyon, police used water cannons and tear gas at the end of a demonstration attended by about 2,000 people.

The Paris demonstration was called by a pressure group campaigning for justice for Adama Traore, a young black man who died in police custody in 2016.

Traore's sister Assa Traore called on those attending the rally to "denounce the denial of justice, denounce social, racial, police violence."

She drew a direct parallel between Floyd's death in the US city of Minneapolis and that of her brother, and renewed her call for a full investigation into his killing.

The rallies came at the end of a week when France's police watchdog revealed that it had received almost 1,500 complaints against officers in 2019 - half of them for alleged violence. 

French Interior Minister Christophe Castaner on Tuesday promised "zero tolerance" of racism in law enforcement, saying it is clear some officers "have failed in their Republican duty."

His comments prompted several dozen police officers to gather with their patrol cars at Paris's Arc de Triomphe on Saturday night, throwing down their handcuffs in protest.

Brut Yoann Maras, a representative from police union Alliance, told AFP: "My colleagues felt let down, abandoned by their supervising minister."

AFP