Facebook said it would block the livestream of a Frenchman suffering from an incurable condition who wanted to broadcast his death on the social media platform.
Earlier, Alain Cocq announced that he was now refusing all food, drink and medicine after President Emmanuel Macron turned down his request for euthanasia.
Mr Cocq, 57, who suffers from a rare condition which causes the walls of his arteries to stick together, said he believed he had less than a week to live and would broadcast his death from Saturday morning.
"The road to deliverance begins and believe me, I am happy," he wrote on Facebook shortly after midnight in a post announcing he had "finished his last meal".
"I know the days ahead are going to be difficult but I have made my decision and I am calm," he added.
Facebook has been increasingly criticised over the way it polices the content it carries and said Saturday (local time) its rules did not allow it to portray suicide.
"Although we respect (Mr Cocq's) decision to want to draw attention to this complex question, following expert advice we have taken measures to prevent the live broadcast on Alain's account," a Facebook spokesman said.
"Our rules do not allow us to show suicide attempts."
Calls on supporters following Facebook decision
Mr Cocq had been trying to post another video earlier Saturday when he messaged: "Facebook is blocking my video broadcast until September 8."
"It is up to you now," he said in a message to supporters before giving out Facebook's French address "so you can let them know what you think about their methods of restricting free speech".
"There will be a back-up within 24 hours" to run the video, he added.
Mr Cocq had written to Mr Macron asking to be given a substance that would allow him to die in peace but the president wrote back to him explaining this was not allowed under French law.
Mr Cocq has used his plight to draw attention to the situation of terminally ill patients in France who are unable to be allowed to die in line with their wishes.
"Because I am not above the law, I am not able to comply with your request," the French president said in a letter to Mr Cocq, which the patient published on his Facebook page.
"I cannot ask anyone to go beyond our current legal framework... Your wish is to request active assistance in dying which is not currently permitted in our country."
‘With profound respect'
In order to show France the "agony" caused by the law in its current state, Mr Cocq planned to broadcast the end of his life - which he believed would come in "four to five days" - on his Facebook page, he told AFP.
He said he hoped his struggle would be remembered and "go down in the long term" as a step towards changing the law.
Mr Macron said in his letter that "with emotion, I respect your action".
The president added a handwritten postscript: "With all my personal support and profound respect."
An official from the president's office told AFP that Macron wanted to hail Mr Cocq's commitment to the rights of people with disabilities.
Right-to-die cases have long been an emotive issue in France.
Most polarising was the case of Vincent Lambert, who was left in a vegetative state after a traffic accident in 2008 and died in July last year after doctors removed life support following a long legal battle.
The case divided the country as well as Mr Lambert's own family, with his parents using every legal avenue to keep him alive but his wife and nephew insisting he must be allowed to die.
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