MONTREAL - Montreal's downtown core was choked by tens of thousands of red squares on Tuesday afternoon during one of the largest demonstrations held to date in the protests that have roiled Quebec for 100 days.

While the march's route was shared with police at least eight hours before the thousands marched through downtown, part of the protest was organized in defiance to emergency legislation passed last Friday.

According to organizers, the demonstration rivaled the size of the protest held on March 22, a protest that many believed was attended by up to 200,000, but others estimated at around 75,000. (There is no agency that provides official crowd estimates in Montreal.) Tuesday's march was planned by a coalition of 140 community groups and unions.

The protest route, planned by student groups FEUQ and FECQ, was set to begin at Place des Festivals, head north on Sherbrooke St., then continue east until going north on Avenue du Parc Lafontaine before entering the park itself.

Sergeant Ian Lafreniere said Tuesday morning he had a strong feeling "all will go well today" given the co-operation student and community groups were showing.

However at the first opportunity to deviate from the planned route, thousands of people holding a large CLASSE banner, turned west on Sherbrooke St.

That separate group then turned south on Peel St., and east along Rene-Levesque Blvd.

While polls in recent weeks suggested the striking students had lost considerable public support, they appeared to have been galvanized in recent days by the new Quebec law.

Parallel events were organized Tuesday in New York, Toronto, Calgary and Vancouver, which saw only a tiny group of people show up to protest. In France, a few hundred congregated near Paris' famous Notre Dame Cathedral.

Law challenge in court

Gabriel Nadeau-Dubois, one of two official spokespeople for CLASSE, said his group is trying to prove that a peaceful protest can take place without abiding by the emergency legislation called Law 78.

"It's not that we are going to defy every law and that we don't care about every law and that we will organize civil disobediences against every law," said Nadeau-Dubois. "What we have said is that this specific law and the specific articles in this specific law are, for us, clear attacks to our fundamental rights."

Speaking in Quebec City, Public Security Minister Robert Dutil said a court challenge was entirely appropriate. Dutil said it is the right of citizens to disagree with the emergency legislation, but that there are appropriate venues for disagreement.

"In a democratic society, when we pass a law, laws can be challenged. and if the courts say we have erred and must change the law, we will change the law," said Dutil.

"What we ask is, if the people who challenge the law, will they respect whatever decision is made? They did not do so when it came to injunctions handed down by those same courts."

Dutil read from a list of cities with equally tough, or even tougher, rules for organizing protests. He listed Geneva, Toronto, New York, Los Angeles, France and Spain as jurisdictions that require far more than eight hours' notice—up to 40 days, in the case of L.A.—in order to hold a protest.

Quebec Solidaire MNA Amir Khadir says the only way to restore social peace is for the Charest government to negotiate with students.

He is also encouraging people to fund a court challenge of Law 78 and is calling for widespread civil disobedience.

"By demonstrating in a peaceful, non-violent manner, by contesting the law in front of the courts and by supporting the student movement in their just struggle against an unjust law," said Khadir.

Student leaders said the idea that negotiations could take place was unlikely.

Martine Desjardins of the university association FEUQ said that talks could not take place "while we have a threat hanging over our heads."

For his part Leo Bureau-Blouin of the college group FECQ said that law 78 will be challenged.

"Our lawyers are not 100 percent certain," said Bureau-Blouin "but we think we have a strong chance of winning in court."

Meanwhile CAQ leader Francois Legault said the only way to solve the conflict is at the ballot box.

While pushing for fixed election dates, he urged Premier Charest to announce now that he would drop an election writ in September, sending Quebecers to the polls in October. Charest did not respond to that comment.

Peaceful protest Monday

Monday's Fete des Patriotes was host to a largely peaceful march throughout Montreal. The protest was the 28th night in a row of marches throughout the city, and the fourth since the emergency legislation passed requiring protesters to notify police of their route.

This protest began with several hundred people at Place Emilie Gamelin, then went to the Jacques Cartier Bridge where police prevented them from staging an sit-in on the roadway.

At any point during the demonstration, police could have declared the protest illegal and arrested people for breaking Law 78, but officers said they did not want to spark a riot.

Demonstrators said they felt civil disobedience was more important than respecting the law.

"The problem isn't with us breaking the law, the problem is with the law," said one woman pushing a baby stroller. "I don't think you can come and make a special law just when it's convenient for you to stop what is one of the most important social movements that we've seen since I have been alive."

The demonstration then headed to Westmount, growing along the way to the point where several thousand protesters were in the streets. The noisy crowd yelled "Wake up Westmount."

CTV reporter Daniele Hamamdjian reported that one resident told her a protester defecated on a neighbour's lawn.

The demonstration tried to make its way to Premier Jean Charest's home but was blocked by a line of police officers at the foot of Victoria St.

The night ended with two arrests for mischief, after people threw objects at police, damaged a car and broke a bank window.

With files from The Canadian Press.