Four people, including a mother and two children aged 3 and 5, were shot dead on Sunday at 11:30 a.m. local time at a station in the northeastern French region of Oise, local media reported.
According to French daily newspaper Le Parisien, the victims were allegedly helped by a friend of the family to leave the city when two suspects shot them.
One of the suspects, who could be the companion of the deceased, then killed himself, according to Le Parisien. Other media reports said the suspect was father of the two children.
While the other suspect fled on foot and was sought after by security forces.
The perimeter of Noyon railway station has been completely closed. Search is under way with a helicopter flying over the site in support of police forces deployed in and around the city.