Witnesses say the woman, thought to be in her thirties, seemed to throw herself out of the window with her son in her arms at about 1.30pm on Sunday.
The circumstances around the incident are not yet clear, but neighbours of the family told Le Parisien the woman and her husband regularly argued.
“It was known in the building that they had family problems,” said one neighbour.
“The police were called during the last few arguments but the woman didn’t want to press charges.”
Police on Sunday questioned the woman’s husband and neighbours about the incident.