Hundreds of teenagers are erecting barricades outside their schools and marching through Paris to protest police expulsions of immigrant families.

Anger erupted this week over the treatment of a 15-year-old Kosovar girl, detained in front of classmates on a field trip. The government says her family had been denied asylum and was no longer allowed to stay in France.

Such expulsions occur regularly around France as the government tries to limit illegal immigration. The students, saying the expulsions are unfair to children, hope to pressure the Socialist-led government into allowing a recently expelled Armenian boy and the Kosovar girl to return to France.

At one high school in Paris, students piled green garbage cans in front of the entrance and hung a banner saying "Education in Danger."