The graphic video, just shy of three minutes, resembles a hardcore wrestling match and created a huge buzz on the Internet on Wednesday.
In it, patrons whipped chairs, plates, bottles, glasses and anything else they could find at each other.
The brawl occurred about 4 a.m. on New Year's Day.
Montreal police say they received multiple 9-1-1 calls for the restaurant and arrived on the scene in about three minutes.
By that time, however, the melee had ended.
"No one was willing to press charges or testify in this case so that's the reason why our investigation is pretty much closed," said Sgt. Ian Lafreniere, a Montreal police spokesman.
The restaurant owner was one of those who refused to get involved, he said, as well as two people who suffered minor injuries and refused transport to the hospital.
Lafreniere said he was not happy to see the video of the fight on the Internet.
"It's a way of glorifying that kind of event, maybe giving other people the same idea of doing this, especially in a case where there's no accusations, no one has been apprehended and no one will be charged," he said.
"I don't really like that kind of message to be spread."
The video is titled "Chinese vs Blacks," but police could not say whether it was a racially motivated attack or a battle between rival gangs.
Besides the video of the incident, police have little else to go on.
The video was allegedly shot at the New Dynasty Restaurant in Montreal's Chinatown district.
The video has been viewed more than 180,000 times on the World Star Hip Hop website since it was posted on Tuesday.
U.S. website The Smoking Gun also picked up the video and the story.Suggest a correction