French President Nicolas Sarkozy has ordered 300 illegal camps of travellers and Roma to be dismantled.
People in the camps found to be living illegally in France would be expelled, he said.
The order is a response to riots last week in which travellers attacked police in a Loire Valley town after a youth was shot dead.
The government said the camps are sources of crime but critics say an ethnic minority is being singled out.
"Within the next three months, half of the illegal camps will be dismantled - camps and squats - that is to say some 300," said Interior Minister Brice Hortefeux after a special government meeting.
A statement issued by the president's office after the meeting described the illegal camps as "sources of illegal trafficking, of profoundly shocking living standards, of exploitation of children for begging, of prostitution and crime".
The meeting was called to discuss the riot in the small Loire Valley town of Saint Aignan, where dozens of travellers armed with hatchets and iron bars attacked the police station, hacked down trees and burned cars.
The riot erupted after a gendarme shot and killed a traveller who had driven through a checkpoint, officials said.
Mr Sarkozy has promised that those responsible for the violence would be "severely punished".
His office also announced that new legislation would be drafted before the end of the year that would make it easier to expel illegal Roma travellers "for reasons of public order".
There are hundreds of thousands of Roma or travelling people living in France who are part of long-established communities.
The other main Roma population is recent immigrants, many from Romania and Bulgaria, who have the right to enter France without a visa but must have work or residency permits to settle in the long-term.
Mr Hortefeux said the new measures "are not meant to stigmatise any community, regardless of who they are, but to punish illegal behaviour".