Michael Schumacher is in a Paris hospital.
The F1 legend, who has not been seen or heard of publicly since sustaining brain injuries in a 2013 skiing crash, was admitted to the Hopital Europeen Georges-Pompidou on Monday, according to Le Parisien newspaper.
The report said the 50-year-old is receiving treatment in a cardiovascular surgery unit by professor Philippe Menasche, a specialist surgeon in heart failure cell therapy.
Menasche, a pioneer in engineered heart tissue, is known for his groundbreaking stem cell research.
Le Parisien said Schumacher's treatment involves stem cell infusion for an anti-inflammatory effect. The great German is expected to return to his home in Switzerland on Wednesday.
The report said Schumacher arrived by a Geneva-registered hospital, along with an entourage of about ten people including his own doctor Gerard Saillant.
Schumacher has reportedly received the stem cell treatment on at least two other occasions. His latest visit was originally scheduled for July, but was postponed for health reasons.