LONDON (CNNMoney) -- Europe's top court has ruled that employers can ban staff from wearing a headscarf.

The European Court of Justice ruled Tuesday on a case concerning two Muslim women who were fired for refusing to remove their headscarves.

The court said companies should be able to ban the wearing of any visible political, philosophical or religious signs. It said a ban on headscarves did not constitute direct discrimination, as long as a general ban on other symbols was in place.

Headscarves could not be banned, however, in response to a request from a customer, it added.

In the first case of its kind, the court touched on an issue that has become a flashpoint across Europe. Debates about Muslim immigration and integration have dominated election campaigns in France and the Netherlands.

The Muslim women -- a receptionist working at G4S in Belgium and a consultant at Micropole in France -- had taken their cases to national courts, who then referred the matter to the ECJ.

G4S is one of the biggest private sector employers in the world, with more than 600,000 workers around the world.