The British Team Ineos rider fractured his femur, elbow and ribs during a high-speed fall.
“Chris was taken to Roanne Hospital where initial examinations confirmed multiple injuries,” said team doctor Richard Usher.
“He is now being airlifted to St Etienne University Hospital for further treatment.”
Team principal Sir Dave Brailsford said their primary focus was on ensuring Froome received the best possible care.
“One of our big strengths on this team is coming together in difficult moments, and we will ensure we do everything possible to support Chris and his family.
“Chris had worked incredibly hard to get in fantastic shape and was on track for the Tour, which unfortunately he will now miss.”
Froome was aiming for a fifth title in the 21-stage Grand Tour, after claiming victories in 2013, 2015, 2016 and 2017.