Vincent Lambert, 38, was left tetrapalegic and in a coma after a motorcycle accident in 2008. In January 2014 his doctors, backed by his wife, Rachel, and six of his eight siblings, decided to stop the intravenous food and water keeping him alive.
The judges said Friday that Lambert's doctors were within their rights, based on their "professional and moral independence," to suspend an earlier court decision that would have seen them cut the intravenous food and water keeping him alive.
Lambert's wife Rachel, his nephew Francois and six of his siblings say the former psychiatric nurse would never have wanted to be kept alive artificially.
On the other side, his devout Catholic parents insist on keeping Lambert alive. His mother Viviane believes her son would improve with better care.
The European Court of Human Rights had in June backed an earlier decision by a French court to allow Lambert to be taken off life support, agreeing that the decision did not violate European rights laws.
According to Friday's court ruling, the decision to stop intravenous feeding can be undertaken "solely by the doctor in charge of care." The hospital may not oppose it.
The judges also ruled that the previous medical decision could not be imposed on a new doctor.
"This judgement throws the burden of responsibility back on to the doctor, who shrinks from the pressure from pro-life activists and members of Vincent's family," Francois Lambert, the nephew, told news agency AFP.
In France, euthanasia is illegal but French MPs on Tuesday adopted legislation to allow medics to place terminally ill patients in a deep sleep. The text must still be examined by the Senate.