The seven-time Formula One world champion crashed while skiing in the resort of Meribel and was airlifted to hospital.
He was wearing a helmet when he hit his head.
The 44-year-old German retired from F1 for the final time in 2012 after a three-season comeback with Mercedes.
Reports claimed the hospital had said he was suffering from "serious brain trauma with coma on his arrival" and had an "immediate neurosurgical operation". His spokeswomen Sabine Kehm said: "Michael fell on his head when he was on a private skiing trip in the French Alps. He was taken to hospital and is receiving professional medical attention. We ask for understanding that we cannot give out continuous information about his health.
"He was wearing a helmet and was not alone. No-one else was involved in the fall."
Earlier yesterday the director of the resort was quoted as saying the injury was "not very serious". Christophe Gernignon-Lecomte said: "It was a pretty heavy fall at 11.00 while skiing off piste. He was conscious after his fall.
"Two or three minutes later, two ski patrols intervened to help him. They immediately asked for a medical evacuation helicopter. It arrived in less than 15 minutes." The former racing driver was taken to hospital in Grenoble and placed under the care of Professor Gerard Saillant, a brain and spine expert.
Schumacher, who also raced for Jordan, Benetton, Ferrari, won the last of his world titles in 2004.
He won two with Benetton in 1994 and 1995 before moving to Ferrari to win five in a row from 2000. He has 91 career wins.
His return to the sport with Mercedes after retirement was less successful. During his first period of retirement, in 2009, he was taken to hospital after a motorbike crash during testing in Cartagena, Spain. He did not suffer serious injuries.