Two policemen were gunned down Thursday near Porte de Chantillon, south of Paris.
According to media reports, they were seen lying on the ground, Xinhua reported.
A suspect has been arrested, a police source said.
French Interior Minister Bernard Cazeneuve quit his emergency inter-ministerial meeting in the Elysee Palace and is on his way to the scene.
Some other reports said one officer was seriously wounded.
There is no link confirmed with Wednesday's attack on Charlie Hebdo magazine. The two suspects of the attack, which left 12 dead and 11 injured, are still on the run. A third, a youngster, surrendered to police later.