A Calais refugee camp known as the Jungle, is home to around 5000 refugees or migrants hoping to eventually cross the Channel to reach Britain.
French authorities are beginning dismantle part of the sprawling site. They say the migrants must move to cleaner and safer shipping containers on another part of the site.
However, many of the migrants fear this will mean they will have to stay in France, and give up their hopes of traveling to Britain.
Overnight, riot police fired tear gas at migrants who were throwing stones at the demolition squads. Some shelters in the camp were set alight.
The authorities believe some 1,000 migrants will be affected by the removal plan.
Most of migrants and refugees have come from places like Syria, Afghanistan and Africa, where there is fighting.