The party thrown by the members of the Rosas de Ouro samba school to celebrate winning the top award at Sao Paulo's Carnival competition ended early after a fight broke out, forcing the school's top officials to their headquarters and send about 10,000 people home.
The fight broke out about 10 pm on Tuesday outside the samba school and police moved in and used tear gas to disperse a number of people in the vicinity.
The tear gas, however, was blown into the hall where the huge crowd was celebrating the school's victory and people rushed for the exits to get to fresh air, leaving the building empty in just a few minutes.
At least 20 people had to receive medical attention due to the irritation caused by the tear gas.
Police said that when some officers tried to break up the fight outside the hall a large group of people hurled sticks and stones at a police vehicle and tried to attack the policemen, who then responded with the tear gas.
The tumult injured two policemen and resulted in five patrol cars being destroyed.
Despite the fact that the situation quieted down in a matter of minutes, the top officials at the samba school preferred to turn off the sound equipment that was providing music for the party, close the doors and announce that the party was over.
Rosas de Ouro this year won its seventh title as champion of the Sao Paulo Carnival celebration with a huge, colourful parade dedicated to cocoa and chocolate early Sunday morning.
The school's victory was announced Tuesday afternoon by the judging panel, and the Rosas da Ouro members started partying immediately thereafter.
The gigantic parades by Sao Paulo's samba schools are the most important such events in Brazil after the world-famous samba parades in Rio de Janeiro.
The parades, which are participated in by up to 6,000 elaborately costumed musicians and dancers, are considered to be the main event at Carnival both in Rio and in Sao Paulo, and attending the samba competition is one of Brazil's main tourist attractions each year.