The incident started as a man called out to the mayor and his entourage as they left council chambers after the passage of a new bylaw tightening rules on demonstrations.
A member of Labeaume's team pushed at the man, who then pursued as the group headed into a nearby hallway. A member of the entourage was shoved from behind and tumbled face-first to the floor.
The man, Labeaume and members of the mayor's group exchanged words, with one man catching the mayor as he appeared to stumble in the fracas. Another member of the entourage pushed police officers toward the protester and he was hustled to the side and arrested.
The entire incident was caught on tape by a Radio-Canada TV camera.
Labeaume at one point yelled at the protester.
"Are you crazy," he said.
Asked about the incident later at another event, Labeaume shrugged it off.
"I've seen worse."
Const. Catherine Veil of the Quebec City police says the protester will be charged with assault.
The bylaw passed at the meeting requires the organizers of demonstrations in the city to provide its itinerary in advance.
It also forbids camping in city parks and prohibits access to parks between 11 p.m. and 5 a.m. Jacques Perron, a spokesman for the city, said the access section will be applied sparingly, in the event of complaints or disruptions.
The legislation was passed in a special session of the city council. Only three of the 27 councillors voted against it.
It had already attracted crowds of protesters inside and outside the council chambers. At one point, police had to control an angry mob inside the city hall who banged on pots and pans to express their outrage.
Police moved them outside, where 21 people were arrested and given tickets in the incident.
Demonstrators were angry that the bylaw was passed just days before Friday's marches by students protesting tuition fee increases. Student organizers have urged massive turnouts for marches in Quebec City and Montreal.
A member of a committee organizing events for the Fete nationale, Quebec's annual June 24 holiday, was also shocked there had been no public consultation on the bylaw.
"At least pretend you're listening to the rest of the world," said Nicolas Lefebvre-Legault of the Comite populaire Saint-Jean-Baptiste.
"Many of the members of the committee who had travelled here to see what was going on were shocked to see this."
Perron said the bylaw was necessary in the aftermath of last fall's Occupy protests.
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