They were also protesting what they called the “false” anniversary of the abolition of slavery, officially marked for the day in 1888 when the Brazilian monarch`s daughter, Princess Isabel, signed the law freeing slaves.
Black Brazilians celebrate the end of slavery on Nov. 20, the anniversary of the killing of Zumbi, a figure of resistance against slavery and the last leader of a runaway slave community called Palmares.
Around 1,000 people marched through downtown Rio de Janeiro in the evening holding candles and signs saying, “Don`t kill me, kill racism,” and accusing far-right President Jair Bolsonaro of genocide through police violence.
Other signs decried the shooting deaths of 28 people in a slum called Jacarezinho on the outskirts of Rio de Janeiro a week ago during an operation that police said targeted drug traffickers.
Human rights activists accused the police of “extrajudicial killings” saying many of the dead were not under investigation.
A Supreme Court justice said he saw signs of “arbitrary execution” in the raid on Jacarezinho.
In São Paulo, a similar number of demonstrators crowded onto the main avenue to oppose racism and police violence.
“We are marking the date of the false abolition of slavery, and the tragedy in Jacarezinho where police ambushed 28 people to kill them in cold blood,” said João de Oliveira.
“President Bolsonaro and his vice president even applauded the slaughter. He committed genocide. We are here to protest.”