Medical staff say Michael Schumacher is "conscious" after undergoing stem-cell treatment in Paris, according to a French newspaper.

The seven-time Formula One champion was admitted to the Georges-Pompidou hospital on Monday, according to Le Parisien, which said he was being treated by cardiovascular surgeon Philippe Menasché, described as a “pioneer in cell surgery".

He has not been seen in public since sustaining serious head injuries in a skiing accident in 2013.

The newspaper said he was due to receive an anti-inflammatory stem cell perfusion on Tuesday and to leave hospital on Wednesday after being transferred from his house in Gland in Switzerland in an ambulance.

The treatment of the former driving ace, whose precise physical and mental state is unknown, is shrouded in secrecy. Mr Schumacher's entourage have issued no comment on the report and the hospital has made no statement about his presence or health.

However, Le Parisien cited an unnamed nurse at the hospital as suggesting he may be showing some signs of recovery.

"Yes he is in my service," the nurse was cited as saying. "And I can assure you that he is conscious."