The woman had been a critical condition since the crash on July 12th at the Bretigny-sur-Orge station.
She was being treated in a hospital in the Paris region but on Monday French media sites, quoting sources close to the inquiry, reported that she had succumbed to her injuries.
Her death, although not officially confirmed, would mean the number of victims killed when the intercity train derailed just south of Paris has risen from six to seven.
Of the six, who were confirmed dead on the day of the disaster two were passengers on the train and four people had been standing on the platform. It is not clear whether the seventh reported victim had been on the train or the platform when the accident occurred.
French rail operator SNCF blamed the accident on a connecting bar that had come loose at a rail switchpoint.
More to follow.