Four-time Formula 1 champion Alain Prost suffered a head injury during a robbery at a home, according to reports in Switzerland.
The Swiss newspaper Blick reported that Prost and his family were the victims of a break-in by a masked gang that took place on Tuesday morning at their home in Nyon.
The report said that Prost's son was forced to open a safe in their home by the perpetrators.
A statement from the Vaud Cantonal Police said a major investigation has been launched, working in cooperation with French police and border security.
The statement said: "According to the first elements of the investigation, on Tuesday morning, May 19, several hooded individuals entered the house.
"Once inside, they threatened the occupants and slightly injured a family member in the head, in circumstances that remain to be established.
"The perpetrators then forced another family member to open a safe before fleeing with loot, the precise inventory of which is being evaluated."
The 71-year-old Prost won the title in 1985, 1986, 1989 and 1993 during a 13-year career that included spells with McLaren, Renault, Ferrari and Williams.
