A baby was killed and several more people seriously injured when a family of 11 threw themselves from a third-floor flat to flee a man they mistook for the devil, French investigators said.

The bizarre tragedy came to light on Saturday when firefighters were called to the village of La Verriere on the outskirts of Paris following reports that several people had jumped from a balcony in a welfare housing block.

Among the injured they found an entirely naked man of African origin with a knife wound in his hand and two children, a baby and a two-year-old girl. The baby died later after receiving hospital treatment in Paris.

The assistant prosecutor from Versailles, Odile Faivre, told reporters the incident began in the early hours when a group of 13 people were watching television in an apartment and the naked man heard the baby cry.

"The man got up to prepare a bottle for the baby when his wife, seeing him, screamed 'It's the devil, it's the devil'," Faivre explained.