Prosecutors investigating Michael Schumacher's ski accident said examination of his helmet camera showed he had left a properly marked out trail at the time of his fall.
Albertville prosecutor Patrick Quincy said the two-minute film from the helmet camera was very clear and showed the former Formula 1 driver lost his balance in the French resort of Meribel and struck his head on a rock.
The fall left him in a critical condition and he has been in a medically induced coma since December 29.
Investigators said they had established the signage on the slopes was in accordance with regulations, but the area where Schumacher was hurt was "virgin territory" so was not marked and could be dangerous.
"There are French standards setting rules on safety, signalling, demarcation ... The checks we have made show these standards had been respected," Mr Quincy said.
However, he said the investigation would take time to establish whether the area where he was skiing could be classed as an "official piste" in French law.
Investigators have visited the scene of the accident in Meribel The video will now be examined by a police expert in mountaineering.
Problems with the rented skis Schumacher was wearing have also been ruled out.
Mr Quincy said Schumacher was "obviously a very good skier" but had not been able to slow himself down in the rocky area of the slope where he fell.
Describing the sequence of events after the former F1 driver went off-piste, he said: "At one point his skis touch a rock, he loses balance and falls forward and his head hits a rock which is 3.5 metres below.
"The rock he hit is eight metres from the edge of the piste and Mr Schumacher on the ground, inanimate, is nine metres from the edge of the piste. That's the information we have with regard to the inquiry."
Early viewings of the helmet camera footage appear to confirm this sequence of events.
Prosecutors said Mr Schumacher's wife Corinna had been 'very co-operative' The inquiry has not yet been able to confirm reports that Schumacher - who was on a family holiday - was going to the aid of a relative when he fell or the speed at which he was travelling, Mr Quincy said.
Police chief Stephane Bozon said Schumacher's speed increased when he entered the steeper off-piste section and he had tried to slow down but had difficulty because of the nature of the slope.
Mr Quincy said investigators have also spoken to emergency services and doctors and visited the scene of the accident.
The Albertville prosecutor's office carries out around 50 investigations into serious skiing and climbing accidents every year, he added.
On Monday, a source said he had made a "slight improvement" but remained in a stable but critical condition.
There was initially speculation that Schumacher was travelling up to 100kph (60mph) when he crashed, after it was revealed his helmet had split on impact.
But subsequent reports suggested he was travelling at a "leisurely pace" of up to 20kph (12mph).
Schumacher, known affectionately as 'Schumi' by fans, is the most successful F1 driver in history, racking up a record 91 race wins.
:: Watch the news conference live on Sky News, on Sky channel 501, Virgin Media channel 602, Freeview channel 82 and Freesat channel 202.
The midfielder played more than 50 times for his country
Water cannon are used in Northern Ireland to control crowds
In 2010, Mrs May said: "No one wants water cannon on Britain's streets"
Calls for the use of water cannon were fuelled by the London riots in 2011
People with a canoe near flood barriers in Oxford
Environment Agency workers check river defence barriers
An Environment Agency map showing the alerts and warnings
Super Junior at the funeral for Park Jeong-su's father and grandparents
The Lusail Stadium will host the tournament's opening match and final
Fans in Doha, Qatar, celebrate winning the right to host the World Cup
Qatar surprised many when it secured the tournament in a 2010 Fifa vote
The helicopter was based at RAF Lakenheath in Suffolk
Police have cordoned off the scene of the crash
Rodman was pictured, shoeless, riding Mr Kim's white horse
Speaking about the leader, Mr Rodman said he "loves the guy"
Raoul Moat was killed after a six-hour stand-off with armed police
Kath Rathband (centre) at her estranged husband's funeral
Emergency service workers carry the coffin of PC David Rathband 
The inquest was shown a dummy pinpointing where the shots hit Mr Duggan
The handgun was a major point of contention in the inquest