By Caroline Wyatt
BBC News, Paris
Police on the border between France and Spain have taken in hundreds of illegal immigrants for questioning as they try to take advantage of a Spanish amnesty.
Many of those stopped claim they cannot speak French or Spanish
The amnesty allowing illegal immigrants working in Spain to obtain permanent resident status was launched on 7 February and runs until 7 May.
It only applies to illegal immigrants who have lived in Spain since last August and hold a work contract there.
But it has encouraged young men to try to enter Spain from further afield.
French border police say most of those detained are from Pakistan and India.
Illegal immigrants are arriving from Paris, Germany and even Italy in the hope of obtaining Spanish residence permits so they can remain in Europe.
Some have lived in France for several years, but without papers or residence permits.
Dozens have apparently tried to cross from France into Spain by car, train, or on foot - but many have been stopped by Spanish police.
They are then driven straight back to France for questioning, a task made more difficult because some of the young men claim not to speak English, French or Spanish, and the police have no Urdu or Hindi translators.
That means the police cannot explain their rights, and so are obliged to let them go - with many making a renewed attempt to enter Spain.