A man wielding a knife stabbed and killed four officers at the police headquarters in the heart of central Paris on Thursday, before being shot dead.

The premises were cordoned off after the lunchtime attack in the historic centre of Paris, usually thronged with tourists, and a dozens of police and emergency vehicles had converged at the scene, AFP journalists reported.

At least one metro station in the vicinity of the building, which is close to Notre-Dame cathedral and other major tourist attractions, was closed.

Sources told AFP the attacker was shot dead by police in the courtyard of the building, where he was employed.

The man worked in an administrative capacity but it was not immediately clear what his precise work role was.

An emergency message was broadcast over loudspeakers at the courthouse next door, announcing "an attack" at the police headquarters and stating the area was "under surveillance".

Interior Minister Christophe Castaner, who was due to visit Turkey later on Thursday, postponed his trip to visit the scene of the attack.

"People were running everywhere, there was crying everywhere," said Emery Siamandi, and interpreter who was in the building when the attack happened.

"I heard a shot, I gathered it was inside," he told AFP. "Moments later, I saw police officers crying. They were in a panic."

Investigators suspect a workplace dispute sparked the deadliest attack on police in France in years, sources said, but there were no immediate further details.

The Paris prosecutor is at the scene, but anti-terror agencies have not been involved at this stage.

"Did he snap, or was there some other reason? It's still too early to say," Loic Travers, head of the Alliance Police union for the Paris region, told BFM television.