The regulations say:
He made one move, then returned to his racing line, leaving one car width as the regulations stipulate. How on earth was the incident Senna's fault?
Schumacher was on the outside and tried to move over to the inside in the braking zone even though there was room on the outside. There was still room for him on the outside, but Michael knew he wouldn't have made the move stick because Senna would have had the line for turn 2. If he wanted to overtake on the inside he should have positioned his car to the right of Senna's, not to the left.