Protesters clashed with police outside a Barcelona and Real Madrid football match at Nou Camp in Spain, the BBC reports.
Thousands of fans inside the stadium held up banners urging the Spanish government to “sit and talk” with those demanding Catalan independence.
The match had been postponed in October over protests against the jailing of nine Catalan separatist leaders.
Many Barcelona fans and other protesters want a legal independence referendum for the region.
Police charged masked protesters who set rubbish bins on fire.
At least 12 people were reportedly injured in the clashes.
The El Clásico was due to be played two months ago but was postponed due to unrest after Spain’s Supreme Court in October sentenced nine Catalan separatist leaders to up to 13 years in prison.
The game ended in a 0-0 draw, leaving Barcelona top the league ahead of Real Madrid on goal difference.