French investigators have said Michael Schumacher's skiing accident was not due to his skis or faulty signage.

The seven-time Formula 1 world champion suffered serious head injuries in a fall in Meribel on 29 December.

The local prosecutor told a news conference in Albertville that the slope Schumacher was on at the time of the crash was prepared according to national standards.

"There are French standards setting rules on safety, signalling, demarcation ... The checks we have made show these standards had been respected," prosecutor Patrick Quincy said.

The 45-year-old is in a critical condition in a hospital in Grenoble, where he was transferred to after the crash.

Investigators said today he hit his head on a rock, about eight metres off-piste, after hitting another rock with his skis.

There is a film of the accident, taken from a helmet camera, which shows what happened.

The investigators used the film to carry out a reconstruction of the accident and will show their findings at an inquiry into the incident.

Investigators said it was hard to make out Schumacher's speed from the film, but he did try to reduce his speed.

They also said the piste and off-piste sections of the slope were well marked.