Protesters including anti-racism groups are planning a rally in Paris in support of victims of police violence.
The demonstration comes after a young black man was allegedly raped with a police baton in a town north-east of the capital in an incident that prompted violent protests in poor suburbs.
Paris police announced a security perimeter in the area for Saturday's rally, while far-right presidential candidate Marine Le Pen urged the government to ban it out of respect for the police.
A 22-year-old youth worker was left in hospital for two weeks after the attack in his hometown of Aulnay-sous-Bois, north-east of Paris. He has become a symbol for minorities who stand up to police violence.
Four police officers have been charged in connection with the case, but deny intentional wrongdoing.