Roma (Gypsies) have blocked a major road bridge near Bordeaux in protest after hundreds of them were evicted from an illegal campsite.
Around 250 vehicles blocked the bridge for five hours on Sunday, causing tailbacks of up to five kilometres on a public holiday weekend.
More than 40 illegal camps have been closed in the past week.
The French interior minister says Roma from Eastern Europe will be deported on "specially chartered flights".
The blockade on the Aquitaine Bridge was the first major counter-protest by Roma and travellers since the French government began its crackdown.
The regional traffic information centre said the blockade caused tailbacks of five kilometres on the Paris-bound carriageway of the A630.
Police said the Roma had been expelled from a camp in the town of Anglet, to the south, and were prevented from setting up a new camp on an exhibition ground nearer Bordeaux.
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 made up of recent immigrants, mainly from Romania and Bulgaria. They have the right to enter France without a visa, but must have work or residency permits to settle over the long term.
The interior minister has announced that he will be meeting Romanian junior minister next week to call on Romanian police to assist in the crackdown in France.