Two suspects have reportedly been arrested following the fatal shooting of a policewoman in Paris, spooking a city already reeling from a massacre at satirical magazine Charlie Hebdo.

Police said it was too early to determine if the shooting was related to Wednesday's massacre in which 12 people were killed, but authorities opened the case as another terrorism investigation.

The police officer was killed after a shootout with a gunman who wore a bulletproof vest and carried a handgun and automatic rifle.

The shooting happened after police and maintenance workers were called to the suburb of Montrouge following a road accident just before 8:00am (local time).

The gunman opened fire on them shortly afterwards, and the trainee policewoman - who was around 20 - was shot in the throat. A maintenance worker was also seriously injured.

It was "a scene of panic," said witness Ahmed Sassi, 38.

From his kitchen window, he said he saw "a police officer standing in the road. A man with dark clothes shot them at point blank range, while continuing to run".

The anti-terrorist section of the Paris prosecutor's office was now handling the probe into the shooting "in view of the current context" following the Charlie Hebdo killing, and also due to the heavy weaponry carried by the attacker and the "deliberate nature of an act targeting security forces".

Meanwhile, a man shot while out for an evening run in a town south-west of Paris, received bullet wounds to the leg and back, a police source said.

The 32-year-old was jogging in the town of Fontenay-aux-Roses when he was struck by automatic gunfire in an attack, although police said it had not been linked to the shooting in nearby Montrouge.

The jogger was in hospital but his life was not in danger, the source said.

Police were still searching for the attacker.

ABC/Wires