Three make shift migrant camps have been evacuated and destroyed in Calais.
Around 200 riot police surrounded the camps housing migrants from Africa, the Middle East and Asia after a deadline to leave expired.
The Governor of the Pas-de-Calais region, Denis Robin, speaking this morning, cited insanitary conditions in the camps and a scabies outbreak which he said was beginning to spread into the town of Calais.
Many migrants left the camps in advance of the operation with some seen leaving hurriedly carrying their blankets.
Migrants' representatives were said to be in talks as to whether they would accept an offer from the authorities of leaving and being rehoused elsewhere in exchange of a promise not to arrest them.
They were being offered the chance to shower, receive medical attention and have a change of clothes, shoes and bedding.
Only one migrant so far has reportedly accepted this offer, while more than 200 are said to have moved into a food distribution centre. They are thought to be reluctant to take alternative accommodation outside Calais as they hope to get into Britain.
The move comes after the French government closed the Sangatte Red Cross centre, near Calais, in 2002 after repeated lobbying by then-home secretary David Blunkett. The camp was said to have been a staging post for thousands of migrants entering the UK illegally.
Aid organisations reported that migrants had made last-ditch attempts to cross the Channel in advance of the police operation.
Border police were said to have spotted groups of 30 to 40 people hiding in shrubs along roads leading into the port. Some were attempting to jump on lorries as they slowed down.
La Voix du Nord newspaper reported later that migrants and volunteers at the food distribution centre have been given until tomorrow or Friday before they are forced to move out of Calais.
It said that 15 of the migrants have already agreed to move into alternative accommodation outside the town.
A spokeswoman for Mr Robin said she could not give further details of the negotiations for the time being.