0533 GMT June 24, 2019
Investigators have ruled out a terror motive, saying the driver had allegedly tried to kill himself the day before, AFP wrote.
"He's confirmed that he had taken large amounts of medication," the legal source said.
"We still don't understand his motive from what he's told us so far," the source added.
The crash in the village of Sept-Sorts, 55km east of Paris, killed a girl aged around 12 years and left five other people seriously injured, including her three-year-old brother.