A German court ruling that the children of foreigners must attend state schools has outraged expatriate families and private international schools which must now seek state permission before admitting pupils.
It came after a Jordanian couple challenged a state ban on their son attending the controversial private King Fahd academy instead of the local state school in Remagen, where the family lives. The academy, which is in Bonn, was set up in 1995 with Saudi funding.
The court backed the ban, saying the country had an interest in "preventing parallel societies" from developing and that state schools were better equipped to "prepare foreigners to live in Germany's cultural setting".
The ruling appears to override the principle of school choice, making it subservient to "integration", says Jan de Groof, president of the European Association for Education Law and Policy in Antwerp, Belgium. He described it as "totally unacceptable" and against European and international law.
"It is not up to the state whether pupils attend public or private, confessional or secular schools. That would be an unacceptable state monopoly," he said.
The principle of integration will also be incorporated into a new school law in the state of North Rhine Westfalia (NRW), which could affect some 40 private international schools in that state.
Stuart Horton, administrative director of St George's school, a British international school in Cologne, said: "Should this law be passed the way it stands, it will affect every English international school in NRW."
German law says that only the children of diplomats and those staying short term may be exempt from attending state schools.
But headteachers fear that the considerable flexibility shown by local authorities in interpreting parents' wishes will be lost.
The state authorities are keen to dispel expat fears saying that the King Fahd academy is a special case. The academy has been under surveillance by Germany's equivalent of MI5, the Verfassungsschutz, for promoting a radical brand of Islam.
Police said the school's curriculum had attracted radical Islamists from elsewhere in Europe. In recent years more than 200 Arab families had moved to Bonn to be near the school, they said. But such comments have angered parents who say they will take their case to the European Court of Human Rights.
"People just want to send their children to a school where they have contact with Arabic and Arab culture," said one parent.
The German Muslim League in Bonn said the ruling would worsen the problem of integration rather than solve it.
"Integration will not be achieved by a few extra lessons in German," the league said.
Plans have been drawn up for eight new German-Turkish bilingual state schools in NRW to cater for the needs of Germany's largest ethnic minority when the ruling becomes law at the end of the year.