Migrants and refugees staged rooftop protests on their ramshackle homes in the Calais camp known as the Jungle in an apparent last-ditch bid to halt demolition teams from dismantling their shelters.
Teams with chainsaws and hammers returned to carry out mass evictions for a second day at the slum - home to around 4,000 people, many of whom want to reach Britain.
Riot squad officers with batons, tear gas canisters and riot shields gathered en masse in the camp, while rows of police vans parked on the edge of the site.
Some migrants sat on top of their shacks, while covered with blankets, in an attempt to prevent contractors from demolishing their shelters within the camp's southern area.
Bulldozers and water cannon moved in following a court ruling in Lille last week approving the site's partial clearance, apart from social spaces including schools and places of worship.
French authorities want to relocate people from the squalid, rat-infested site to heated containers nearby or to centres around France where they can apply for asylum. State authorities have said up to 1,000 people will be affected.
But aid workers say the figure is likely to be much higher. Help Refugees said its own analysis revealed there were 3,455 people living in the affected area.
Save The Children said nearly 400 unaccompanied children who have fled war, poverty and persecution live at the site.
Campaigners had called for a postponement to remove people from the slum, saying there was not enough new accommodation for people to move to.
Some have criticised the decision to send in demolition teams, including Liberal Democrat leader Tim Farron, who said razing the camp was not the solution.
But British hauliers welcomed last week's court's judgment.
The Freight Transport Association (FTA) said disruption caused by migrants cost the UK freight industry an estimated £750,000 a day last year.
FTA officials said a solution needed to be found to protect the £89 billion of UK trade which passes through cross-Channel ports annually.
Calais has lived with migrants in its midst for years, but the current camp on the city's edge sprang up around a day centre opened last April by the state - and has grown explosively.
Repeated bids to cross the Channel to Britain have been made by migrants, prompting an Anglo-French operation to bolster security around the ports, including the erection of razor-topped fences.