Demolition teams have begun pulling down tents and makeshift shelters in the sprawling migrants' camp in Calais, observed by hundreds of riot police.
A flashpoint on the edge of the Channel, the camp known as the Jungle sprang up less than a year ago in the port city.
It has grown explosively in past months amid Europe's migrant crisis, fuelling far-right sentiment in both Britain and France.
Some 4,000 people are estimated to live in the camp - down from 6,000 in December.
Calais has lived with migrants in its midst for years, but the current camp on the city's edge grew around a day centre opened last April by the state.
Scores of riot police stood guard, keeping journalists and volunteers out as helmeted workers tackled the shelters one by one.
Prefect Fabienne Buccio, who had ordered the camp evacuated and dismantled earlier this month, arrived as the operation began.
She said: "Really three houses out of four - I mean three huts out of four, or three tents out of four - were already totally abandoned with a lot of garbage inside."
Migrants, she said, "had the time necessary to gather their belongings. The rest was good enough to throw away".
However, cameras zooming into huts captured scenes of daily life fully intact.
The start of what is likely to be a weeks-long operation came four days after a court ruled that shelters could come down - but not common areas like houses of worship, a school, a women's centre and a library, much of it built with the help of French and British volunteers appalled by conditions in the makeshift camp.
Humanitarian groups and migrants who had contested the state decision to level the most populous sector of the camp filed an appeal against the ruling on Friday with the Council of State, but any decision is likely to take weeks or months, long after the camp is gone.
French authorities are offering to relocate uprooted migrants into heated containers installed last month nearby, or at centres around France where they can decide whether to apply for asylum.
Many have resisted the move, fearing it will hurt their chances of reaching Britain, and some migrant advocates say there is not enough space in the new area.