PARIS | A French investigating judge has filed preliminary charges against a physicist at the world's largest atom smasher who is suspected of al Qaeda links, a judicial official said.

The 32-year-old Frenchman of Algerian origin, who works on the Large Hadron Collider, is suspected of involvement with al Qaeda in the Islamic Maghreb, a North African group that targets Algerian government forces and sometimes attacks foreigners. He was arrested Thursday in France.

Investigating magistrate Christophe Teissier filed charges against the suspect for "criminal association with a terrorist enterprise," a broad charge that is often used in terror-related cases in France, said the official, who spoke on the condition of anonymity because the investigation is ongoing...