Police used tear gas to disperse dozens of migrants who lined up to prevent them pulling down the makeshift camp. Hundreds of tents and temporary shelters were torn down.
Video footage posted on social media on Monday showed police releasing several canisters of tear gas inside the camp, which sprang up in the northern French port town less than a year ago.
A group of about 150 migrants and activists threw stones at riot police as construction workers began dismantling hundreds of temporary structures in the camp's southern section, which have served as homes for migrants hoping to make their way across the English Channel to Britain.
Three makshift shelters were set ablaze and one person was arrested during the clashes.
Dozens of officers stood guard, keeping journalists and volunteers out as helmeted workers took down the shelters one by one.
Shock and anger
Several volunteers, who have spent months trying to improve conditions in the shantytown, were shocked when police suddenly moved in.
"We didn't think that it would happen with so many police. It's infinitely sad to see the waste of so much work that we've done in the past months," Maya Konforti, of the Auberge des Migrants charity, told the AFP news agency.
Prefect Fabienne Buccio, who had ordered the camp's destruction, said migrants had been given the time necessary to gather their belongings and that many of the structures had already been abandoned.
But video footage filmed on Monday still showed the usual daily signs of life in parts of the camp.
Some 4,000 people are estimated to live in the "Jungle," which sprang up last year after several smaller sites were bulldozed.
Judge gives deadline
Buccio's expulsion order was upheld by a judge last week after a legal challenge.
Human rights groups have lambasted the move, saying that limited housing alternatives are being offered to the migrants, despite assurances from local authorities.
A 1,500-person-capacity accommodation centre made of shipping containers has been built nearby, and French officials have encouraged migrants to apply for asylum in France and move to other parts of the country with more appropriate accommodation.
The judge ordered that several structures within the camp remain untouched, including churches and mosques, a school and centers for legal and health assistance. The dismantling of the rest of the camp is expected to take several weeks.
A previous attempt to tear down the shantytown on Friday was delayed after what authorities called "extremist activists" prevented them from making much progress.
Calais has been a temporary home for thousands of migrants - fleeing war and poverty - for more than two decades. Several attempts to disperse them have only succeeded temporarily as many eventually returned to the Calais area and were joined by newcomers that have traveled through Europe to reach the coast.
Hundreds of them have made it to the UK by hiding in lorries, which use the Eurotunnel or ferries connecting France or the UK.
One Sudanese man, who crept through the Channel Tunnel under total darkness, made it to Britain and was eventually granted asylum.
mm/rc (AFP, AP, dpa, Reuters)