Former Formula One world champion Michael Schumacher was admitted to a Paris hospital for "secret treatment" earlier on Monday, Le Parisien newspaper reported.
Schumacher turned 50 on January 3 but has not been seen in public since a skiing accident in the French Alps five years ago that left him with severe head injuries and in a medically-induced coma for several months.
Schumacher was taken to the Pompidou hospital in southwest Paris on Monday afternoon, Le Parisien said, without citing its sources.
"The treatment will begin on Tuesday morning and (he will) leave the establishment on Wednesday," said Le Parisien, which claims the former Ferrari star has already been treated there twice this spring.
The French newspaper said the former champion would undergo treatment based on stem-cell transfusion by French surgeon Philippe Menasche.
A spokeswoman for Schumacher did not immediately return a request for comment.
Schumacher remains motor racing's most successful driver, with a record 91 grand prix wins. He won his first two titles with Benetton in 1994 and 1995 before five in a row with Ferrari between 2000-2004.
In January his family released a statement saying he was in "the very best of hands".
Schumacher had won his first Grand Prix back in 1992. His spent his most successful years at Benetton and Ferrari, for whom he won the last of his 91 Grand Prix victories in China in 2006.
He came out of retirement in 2010 for a three-year stint with Mercedes.
According to AFP, Fans revere the determined German and his name was chanted at the Monza circuit last weekend for Ferrari's most successful Formula One driver Schumacher, with his son Mick, who is part of the FerrariDriverAcademy, present.