French investigators have ruled out any criminal wrongdoing in the ski accident of former Formula One world champion Michael Schumacher and have closed the case.

Schumacher, 45, has undergone two operations since sustaining brain injuries after hitting his head on a rock while skiing off-piste in the French Alps resort of Meribel.

The seven times world champion was in a stable but critical condition until late January and doctors in the Grenoble hospital have started waking him up progressively by lowering his sedation.

The investigators tried to determine if any third party was responsible for his accident and if Schumacher was aware that he was skiing beyond the marked-out zone.

“The investigation into the causes and consequences of the skiing accident of Michael Schumacher has been closed,” the authorities said in a statement.

“No person has been found guilty of any violation.”

“Signalling, demarcation and information given on the limits of the piste were in line with the French standards,” the prosecutor added.

Schumacher, who quit the sport in 2012 after a disappointing three-year comeback with Mercedes following an earlier retirement from Ferrari at the end of 2006, has won a record 91 grands prix.