The premises were cordoned off on Thursday after the lunchtime attack in the historic center of Paris, usually thronged with tourists, and a dozen emergency vehicles were at the scene, AFP journalists reported, according to presstv.ir.
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 said 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 court of justice 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, has postponed his trip to visit the scene of the attack.
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.
Succession of attacks
There was no immediate indication of the possible motives of the attacker.
France has since 2015 been rocked by a succession of attacks blamed on terrorists, which have seen both large synchronized assaults and also isolated knife attacks, claiming some 245 victims.
The country remains on high alert after these attacks.
In January 2015, two men armed with Kalashnikov rifles stormed the Paris offices of satirical weekly Charlie Hebdo, killing 12 people. A policewoman was killed just outside Paris the following day, while a gunman took hostages at a supermarket, four of whom are killed.
On November 15 that year, France was hit by the worst terror attacks in its history.
Daesh terrorists armed with assault rifles and explosives struck outside a France-Germany football match at the national stadium, Paris cafes, and the Bataclan concert hall in a coordinated assault that left 130 people dead and more than 350 wounded.
On July 14, 2016, a Tunisian plowed a truck through a large crowd gathered for Bastille Day fireworks in the Mediterranean city of Nice. The attack killed 86 people and injured more than 400.
And in May 2018, a knifeman was shot dead by police in central Paris, after killing one person and injuring four with a knife close to the Opera metro station in central Paris.