An Asian mother who fell from a fourth-floor apartment and her two young children, apparently stabbed, were found dead in Val-de-Marne southeast of Paris on Monday, witnesses and officials said.

The mother, aged around 40 and dressed in red when she died, fell out of the fourth floor of a residential building, a judicial source said.

The body of the Asian woman could still be seen lying on the ground Monday afternoon, surrounded by police investigators, an AFP journalist said.

A baby and a child aged five or six years died in the apartment above, apparently stabbed to death with a knife that was left next to one of the tiny victims' bodies.

Two police sources said initial probe results suggested that the woman killed the two children before throwing herself out of the window.

However the judicial source said it was too early to put forward a hypothesis.

Shocked neighbours watched as police rushed to the apartment where the tragedy took place in a leafy, residential area southeast of the French capital.

"I heard a noise and boom, I saw her lying there. A fireman in civilian clothing called his colleagues, who rushed here" and tried to resuscitate the woman, said Sikirou Salaou, a security guard at a nearby supermarket who witnessed the fall.

"A neighbour told the firemen: 'There are children up there,' and they rushed up," Salaou added.

Another baffled neighbour, Gomez Goncalves, said the dead woman "had two little boys. She was nice, calm," and had lived in the neighbourhood for at least 10 years.

Goncalves said the mother had had a series of successive partners in recent years, but could not confirm whether she was seeing anyone at the time of her death.

"There were never any arguments," he said.