French police were evacuating several hundred migrants from a makeshift camp in a forest near Dunkirk.
The prefecture of the Nord region confirmed that an evacuation was in progress at the camp on Tuesday and the migrants were being taken to shelters.
The regional newspaper Nord Littoral reported that hundreds of police were putting migrants on buses.
It said some 350 migrants were staying at the camp in the Grande-Synthe region outside Dunkirk.
Migrants trying to sneak across the English Channel to the UK have been living in forested areas since an official camp of wooden shelters, housing some 1,500 migrants, burned to the ground in April.
Tuesday's operation came a day after the mayor of Grand-Synthe met in Paris with Interior Minister Gerard Collomb who rejected the opening of a new camp.