Alain Panabière, 53, suffering from morbid obesity, has been stranded at his home in Perpignan for several years.
To get him out on Tuesday morning, more than 50 people were mobilized, including police, firefighters and medical teams.
A "high-risk" operation, according to his lawyer.
He will finally be able to leave his home.
Blocked for years in his house in Perpignan, a man of about 300 kg is being evacuated on Tuesday, in a very delicate operation where his life is at stake. For this "high-risk operation" according to his lawyer Jean Codognès, a classic escape by the stairs was impossible.
Alain Panabière, 53, lives on the floor in an unsanitary house, and cannot pass the door of his room.
After initial consolidation work on the two-storey house located in a district with narrow streets in the center of the Catalan city (Pyrénées-Orientales), a sanitary cordon was installed Tuesday morning.
More than 50 people are also mobilized, including police, firefighters and medical teams, said the prefecture.
A complaint against X
To extract it, part of the facade will be destroyed at the level of the first floor.
The man will then be moved horizontally to a gondola suspended from a crane, which will drop him off at street level, where an ambulance awaits him.
Alain Panabière will first be taken to the Montpellier University Hospital for a "global assessment" of his state of health, before his transfer a few weeks later to a rehabilitation center, according to the head of the Endocrinology-Diabetology-Nutrition department, Antoine Avignon .
Me Jean Codognès had sent a letter at the end of October to the Minister of the Interior Gerald Darmanin to ask him for an urgent intervention.
A few days later, his client and the National League Against Obesity filed a complaint against X for "non-assistance to a person in danger" and "failure to help a person in danger".