Border guards including riot police halted hundreds of mainly North African men who have crossed from Libya and Tunisia.
The trains, on which they traveled and which also contained political activists calling for better rights for immigrants, were attempting to cross from the nearby Italian border station of Ventimiglia.
Italy infuriated the French last week by giving out temporary residence visas, allowing the immigrants to travel in the European Union.
Many want to go to France because they speak French, and because they believe that President Nicolas Sarkozy's approach to the war in Libya means he will be sympathetic to them.
But the French government insists it will only allow in those with the financial resources to live in France independently.
Katie Pavlich is the Editor at Townhall.com. Follow her on Twitter @katiepavlich. She is a New York Times Best Selling author. Her latest book Assault and Flattery: The Truth About the Left and Their War on Women, was published on July 8, 2014.