A French court on Thursday gave the green light to plans to evacuate hundreds of migrants from the notorious "Jungle" camp in Calais as the mayor said the process would take place over the next three weeks.
Activists had appealed to the court to stop the evacuation of the southern half of the sprawling camp in the port town, with many of the migrants wanting to stay near the entrance to the Channel Tunnel, the gateway to their ultimate goal of Britain.
But an official at the court in Lille said the decision to clear part of the Jungle had been "validated".
Calais town authorities have promised that no one will be evacuated from the Jungle by force.
The mayor, Natacha Bouchart, said: "I am satisfied by this responsible decision which will allow the progressive dismantling of the southern part of the Jungle to proceed over the next three weeks."
An official who asked not to be named said discussions would continue with migrants' representatives to persuade the migrants to leave "so that they have a roof over their heads".
French Interior Minister Bernard Cazeneuve welcomed the court's decision, saying it backed up the authorities' moves to clear part of the camp.
"The operation to put the refugees under protection will continue, using all of the existing accommodation solutions," he said.
Local authorities say there are a total of 3,700 residents in the camp, and that between 800 and 1,000 will be affected by the eviction.
But charities say a recent census they conducted found at least 3,450 people living in the southern part of the Jungle alone, including 300 unaccompanied children.
The evicted migrants have been offered heated accommodation in refitted containers set up next door to the camp, but many are reluctant to move there because they lack any communal spaces and movement is restricted.
They have also been offered places in some 100 reception centres dotted around France.
The migrants in Calais make up a tiny fraction of those fleeing war and poverty in the Middle East and Africa.
They try to climb on to lorries boarding ferries for Britain, which they are drawn to by family or community ties, because of a shared language, or because they think they have a greater chance of finding work there.
The Jungle has also played into fraught discussions about Britain's possible exit from the European Union.
Some opponents of "Brexit" say that if Britain were to leave the EU, the British government would lose the ability to call on France to stop the refugees from trying to make their way across the Channel.