Michael Schumacher's former Mercedes boss has called on the Formula One driver's family to provide more information about his condition.
French newspaper Le Parisien claimed on Monday that Schumacher, who has not been seen in public for almost six years following his skiing accident, has been admitted to a Paris hospital for "secret treatment".
Schumacher's management have declined to comment on the latest report.
Schumacher has been recovering at the family home in Lausanne, Switzerland after he sustained serious head injuries in December 2013. There have been few updates about his well-being.
To coincide with his 50th birthday last January, the family issued a rare statement, saying they "are doing everything humanely possible" to help the seven-time world champion, and "that he is in the very best of hands".
The wall of secrecy, enforced at the request of Schumacher's wife Corinna, was established to protect one of the biggest names in modern sporting times.
But, writing in his forthcoming book, Nick Fry, who worked alongside Schumacher for three years at Mercedes, believes the sporadic offerings about a driver who won a record seven world championships, 91 grands prix, and commanded a following of millions around the world, are not enough.
Michael Schumacher through the years
Michael Schumacher through the years
Ferrari's Michael Schumacher sprays the victory champagne in front of an emotional Jean Todt after winning the race and securing his 5th World Driver's Championship
Michael Schumacher of Germany poses during a photo call at the Bongarts Studio in 1991 in Hamburg.
Michael Schumacher poses in a Sauber-Mercedes C291.
Michael Schumacher’s family say 'we are doing everything possible to help him' in rare statement ahead of his 50th birthday.
Schumacher’s trademark leap marked another win at Silverstone en route to the drivers’ championship in 2002.
Despite a disqualification, Schumacher went on to win the 1994 Formula One drivers’ title.
The F1 legend is pictured in 1991.
Michael Schumacher is pictured skiing.
File photo dated 12-07-1998 of Michael Schumacher lifts the trophy after winning the British Grand Prix at Silverstone today. Picture Owen Humphries/PA* EDI *
File photo dated 10-07-1994 of Britain's Damon Hill (center) on the winners Rostrum with second placed Michael Schumacher (left) and Jean Alesi after taking his Williams Renault to victory in the British Grand Prix at Silverstone.
File photo dated 09-06-2006 of Ferrari's Michael Schumacher
File photo dated 11-07-2004 of Michael Schumacher
Scuderia Ferrari's Fernando Alonso (centre) after qualifying in pole position with second place Red Bull Racing Renault's Mark Webber (right) and third place Mercedes AMG Petronas' Michael Schumacher during qualifying for the British Grand Prix at Silverstone Circuit, Silverstone.
Mercedes AMG Petronas driver Michael Schumacher in the garage during the third practice session of the British Grand Prix at Silverstone Circuit, Silverstone.
Mercedes Grand Prix driver Michael Schumacher on a bike before the Monaco Grand Prix at the Circuit de Monaco, Monte Carlo.
Mercedes' Michael Schumacher during the Qualifying Day at the Monza Circuit, Italy.
Mercedes' Michael Schumacher during Third Practice Session during Qualifying for the Santander British Grand Prix at Silverstone Circuit, Northampton.
Michael Schumacher, Mercedes GP
Mercedes' Michael Schumacher makes his way down the pit lane after the practice session at the Circuit de Monaco, Monte Carlo.
Mercedes' Michael Schumacher during the driver's parade prior to the start of the Spanish Grand Prix
Mercedes GP driver Michael Schumacher during the Formula One Testing Session at the Circuit de la Comunitat Valenciana Ricardo Tormo, Valencia, Spain.
Michael Schumacher in the pits during practice day at the Circuit Valencia, Spain.
Germany's Michael Schumacher
Motor racing champion Michael Schumacher launches Rally for Safer Roads in central London.
Ferrari's Michael Schumacher at Silverstone ahead of the British Grand Prix which will be held on Sunday.
World F1 Champion Michael Schumacher in the pits during afternoon practise, at Silverstone, prior to Sunday's British Grand Prix in, Northamptonshire.
F1 World Champion, Michael Schumacher at Dublin Castle, where he attended the formal signing of an historic European Charter on Road Safety. The Charter is a key element of the 'European Safety Drive' action programme thats goal is reducing the number of road deaths in Europe by at least 50% by 2010. According to the Irish Department of Transport, 40,000 people die as a result of traffic accidents in the 15 EU countries, with 1.2 million worldwide killed each year on the roads, or over 3,000 every day.
Pele and Michael Schumacher fool around at the Preliminary Draw in Frankfurt for the 2006 World Cup
Ferrari's Michael Schumacher (l) fools around with jockey Frankie Dettori (r) in the pits
Ferrari's Michael Schumacher, Rubens Barrichello and Technical Director Ross Brawn stand with 3rd placed driver Juan Pablo Montoya and celebrate at the top of the podium after another 1-2 finish
Ferrari's Michael Schumacher, relaxing between sessions sips coffee and chats with Sporting Director Jean Todt
Ferrari's Michael Schumacher celebrates at the top of the podium with Jean Todt after winning his 5th World Driver's Championship.McLaren's David Coulthard lifts the arm of team mate Kimi Raikkonen after he came very close to winning the race
Ferrari's Rubens Barrichello stands at the top of the podium, in between team mate Michael Schumacher and McLaren Kimi Raikkonen
Ferrari's Michael Schumacher prepares for the race
Ferrari's Michael Schumacher celebrates victory in the Canadian Grand Prix.
Racing driver Michael Schumacher arrives for the Laureus World Sports Awards at the Forum Grimaldi in Monte Carlo.
Actor Sean Connery (L) and racing driver Michael Schumacher arrive for the Laureus World Sports Awards at the Forum Grimaldi in Monte Carlo.
Michael Schumacher with his Sportsman of the Year award at the Laureus World Sports Awards at the Forum Grimaldi in Monte Carlo.
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"Corinna and the family have kept a very tight control on information about his treatment which, I think, is a pity," Fry wrote in his book, Survive. Drive. Win., seen by the PA News agency.
"There are millions of people out there who have a genuine affection for Michael, and that's not just his fans in Germany or fans of Mercedes Benz.
"Because of what he achieved, people would like to know about his condition; they are inquisitive and they genuinely feel for him.
"I do think that reporting on how he is, regardless of whether it is good or bad news – and possibly it is bad news – is important because people can empathise with him."
Fry was chief executive for Mercedes during Schumacher's largely unsuccessful second spell in Formula One. He was replaced at Mercedes by Toto Wolff in 2013.
"From what I understand, Michael's family have been able to give him the best treatment that money can buy in a specially constructed facility at the family home in Switzerland where he is looked after by a dedicated team around the clock," Fry continued.
"I am sure that techniques and therapies have been developed and tried there over the last few years that may well help others.
"It would be helpful for his family to share how they have dealt with this challenge because there are lots of people in a similar situation who would probably find it beneficial to have that first-hand experiences."
:: Survive. Drive. Win. The Inside Story of Brawn GP and Jenson Button's Incredible F1 Championship Win is by Nick Fry with Ed Gorman, published by Atlantic Books on October 3.