Former F1 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 in 2013 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 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 and 2004.

In January his family released a statement saying he was in "the very best of hands".