A police source confirmed a report in Le Parisien newspaper, which said the former boss of the Michelin-starred La Reserve was among nine people arrested over the abduction.
Kidnapping victim Jacqueline Veyrac, 76, is the millionaire owner of La Reserve on the Nice seafront and the luxury Grand Hotel in nearby Cannes.
She was already the victim of a kidnapping three years ago, the motive of which was never discovered.
Le Parisien identified the main suspect in the latest affair as Giuseppe S., an Italian, and said he was believed to harbour a grudge against Veyrac.
On Monday, she was snatched as she was getting into her SUV in a busy part of Nice and bundled into a waiting van.
She was found alive and well two days later, in a white van with false number plates parked in the hills above the Riviera resort.
The local prosecutor described the case as “complex” and said it appeared not to be linked to any ransom demand but “something very personal”.
Veyrac, whose husband died five years ago, co-owns the Grand Hotel and La Reserve with one of her sons.
The Grand Hotel is one of the establishments on the palm-lined Croisette boulevard that roll out the red carpet each May for movie stars attending the Cannes Film Festival.