By Caroline Wyatt
BBC correspondent in Paris
A French administrative court has ruled on an appeal brought by three Sikh boys who have been excluded from classes for wearing the under-turban.
Several Sikhs at the school have been turned away from classes
However, it referred the matter back to the boys' school, and said the issue should be resolved by further mediation between the school and its pupils.
France introduced its new law banning the wearing of all religious symbols from state schools from September.
France's small Sikh community says the under-turban is a valid compromise.
They say the boys should not be excluded.
Muslim pupils have also been affected, with at least five girls now expelled for wearing the Islamic headscarf.
The administrative court has been careful not to set a legal precedent that might give Muslim pupils their own grounds for appeal.
It said the school that had excluded the Sikh boys from classes for wearing the under-turban should continue its dialogue with them within the next 15 days.
Other schools in Paris have accepted Sikh pupils wearing only a discreet under-turban.
Muslims say it is their right to wear a headscarf
But that option was rejected by the Louise Michel school, which argued that there could not be different rules for different religions, and that the law must apply equally to all.
The French authorities admit that when the law was drafted, nobody consulted France's small Sikh community.
The law itself was aimed primarily at removing the Islamic headscarf from schools, thanks to French fear of a growing strain of Islamic fundamentalism among a minority of young Muslims in the country.
This week, at least seven girls have been expelled from their schools for refusing to remove the Islamic headscarf or hijab in class - and some are threatening to bring their own legal appeal against their expulsion.