The young woman, a student, was kidnapped from her home in the eastern city of Lyon on Thursday evening by two men pretending to be plumbers, sources close to the case told AFP.
They bundled her into a car before telephoning her father, who works for a Swiss cash-in-transit company that transports money between banks and companies under tight security.
The father, who was out in his van at the time, agreed to hand over its contents at a meeting point in Vaud on the Swiss side of the border - several million Swiss francs (hundreds of thousands of dollars or euros), Europe 1 radio reported.
His daughter was released around 22:00 on Thursday on a highway in the French border region of Ain.
A source close to the probe said there had been no arrests yet in the investigation, which is being led by French police.
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