Montreal police came under criticism Sunday after a video was released showing them spraying bar patrons with pepper spray after a chair was tossed in their direction.

The video shows patrons on the patio at Le St-Bock and police in what appears to be a standoff. A chair is thrown at police and officers respond by firing off several rounds of pepper spray. The two sides clash briefly, and the patrons eventually disperse and take cover inside the bar.

Bar manager Nicolas Paquet said police also fired a crowd-dispersal powder at the patrons gathered on the patio.

"In my eyes, (police were ) violent and rough with the customers," Paquet told CTV Montreal. "All that for only one guy."

Martin Guimond, owner of the bar, said he's considering taking legal action against police.

"People were falling on each other running inside to get away from the pepper spray, breaking things, and then people left by the back exit," Guimond told The Canadian Press.

"My waitress said, 'We have to call 911.' And then she said, 'But wait, it's the police that are doing this.' That's when you realize there's a total loss of security."

Montreal police spokesperson Const. Simon Delorme told CTV Montreal that police were reacting to the chair that was thrown in their direction.

The video comes just one day after violent protests rocked the city streets, resulting in 69 arrests.

Nine people have been charged with criminal offences including armed aggression against police, assaulting police and arson, said Montreal police spokesperson Const. Yannick Ouimet.

Officers also recovered a bag containing Molotov cocktails, said Ouimet.

The protests were in response to the controversial Bill 78 that was passed in Quebec's National Assembly Friday.

The bill -- designed to end the ongoing, three-month-old student protest over proposed tuition increases -- has been heavily criticized by student groups, union leaders and academics.

The legislation ends the current academic year at schools affected by the strike, imposes fines for anyone who blocks access to university campuses and restricts the size and length of protests.

The law also demands that student groups give prior notice before launching a protest and provide police with a full itinerary of the demonstration. Protesters can also be punished for wearing a mask during demonstrations. The bill is considered an emergency measure and will expire in July 2013.

While the government says the law is necessary to bring peace to the troubled city, critics say it is a violation of core civil rights that will only fuel more unrest.

Meanwhile, the student movement has found some celebrity allies.

In New York, Montreal band Arcade Fire wore red squares -- the student movement's iconic symbol -- during a performance with Mick Jagger on Saturday Night Live.

Filmmaker and activist Michael Moore also expressed his support for the movement on Twitter Saturday.

"Canadians are in revolt in Quebec over new gov't law limiting democratic rights. No news of it in US press. Their uprising is inspiring," read the tweet.

Demonstrators took to the streets again Sunday night. Police declared the protest illegal because they had not been provided with a protest route.

Officers used sound grenades in an attempt to disperse the crowd, some of whom threw projectiles at officers.

With file from The Canadian Press and a report from CTV Montreal's Mark Shalhoub