Chloe Rodriguez was discovered by German police near Offenburg, southwestern Germany, close to the French border, during a routine check of a car.
The driver, who came from the same region as the girl and was wanted for robbery in Germany, was arrested, a French police spokesman said.
The girl was taken to hospital but initial indications suggested she had not been harmed.
She had been missing since November 9, when she left her friend’s home on a moped and failed to return. Her parents alerted the police that night, and they found her moped near the friend’s house, with all her personal effects in it except her helmet and mobile phone.
Officers and volunteers then spent five days searching an area of 16 square kilometres around Barjac. Divers were also called in to search local ponds and lakes. Officers also interviewed a number of the girl’s friends and relatives.
Chloe’s mother has revealed that her daughter may have been in a state of emotional distress at the time of her disappearance.
Local police expect to open an investigation into a suspected kidnapping following the recovery of the girl – and have demanded the extradition of the man from Germany.