Former world champion Jenson Button and his wife were reportedly gassed when robbers broke into their St Tropez villa.
Button, who has a reported value of £71m, is believed to be staying in the house with his wife, Jessica Michibata, and three friends on the night the property was targeted by robbers.
According to the Daily Mail, French police informed the Brit that the gang let off a canister of anaesthetic gas into an air-conditioning vent which rendered their guests unconscious as they raided the villa on Monday.
The report suggests that the robbers took Michibata's £250,000 engagement ring and escaped with close to £300,000 worth of belongings.
Button is reported not to have learned about the burglary until finding out the ring was missing the next morning.