More than 1,200 police and officials in France are preparing for the clearance of the "Jungle" migrant camp in Calais.
Authorities say some 7,000 people live in the camp in squalid conditions. They will be offered placements in refugee centres across France.
But there is concern that some migrants will refuse to go because they still want to get to Britain.
There were clashes between the police and groups of migrants over the weekend.
"They'll have to force us to leave. We want to go to Britain," one Afghan, Karhazi, told the AFP news agency.
The UK has begun to accept some of the estimated 1,300 unaccompanied children from the camp.
The first group without family ties to the UK has arrived in Britain under the "Dubs amendment" rules, which grant refuge to the most vulnerable.
Charities are helping the French authorities to process minors that remain in the camp, by conducting interviews and establishing who should also be transferred to the UK.
Amid concerns for their safety, children will be taken to the camp's converted shipping containers while the rest of the Jungle is dismantled, according to the French interior ministry.
The migrants who currently live in the containers - which were being used as temporary accommodation instead of makeshift tents - will be evacuated to make room for them.
About 10,000 leaflets are being handed out by the French authorities, informing people about the plans for the clearance. They are being told report to a reception point and will then be taken to other parts of France and given the opportunity to claim asylum.
There are 7,500 beds available in centres across France for the Calais migrants. Some 60 buses will be used to remove them from the camp.
From Tuesday, heavy machinery will be sent to clear the tents and shelters that have been left behind.
The whole operation is expected to take three days.
The French interior ministry said it "does not want to use force but if there are migrants who refuse to leave, or NGOs who cause trouble, the police might be forced to intervene".
The Jungle has played host to scenes of both squalor and of violence, as migrants, mainly from Africa and the Middle East, attempt to board lorries bound for the UK, clashing with drivers and police in the process.
A UK-funded wall 1km (0.6 miles) long is being built along the main road to the port in an attempt to deter would-be stowaways. The UK government has not confirmed the cost, but it is reported to have contributed about £1.9m (€2.2m).
Work on the wall, which began last month, is due to be finished by the end of the year.