The French mercenary, Bob Denard, has died, his family says. He had been suffering from Alzheimer's disease.
"I confirm that he has died," his sister Georgette Garnier told Reuters.
Denard, 78, was notorious for leading coups in Africa, including four in the Comoros Islands - the most recent of which was in 1995.
He was convicted in French courts for his efforts to overthrow governments in Benin in 1977 and the Comoros, but both jail sentences were suspended.
His trial last year in connection with the 1995 Comoros coup attempt took place with him in absentia as a result of his illness.
Convicted of "belonging to a gang who conspired to commit a crime", Denard received a five-year suspended jail sentence.
Denard was born Gilbert Bourgeaud in Bordeaux in 1929.
After serving in the French navy in Indochina, he joined the police in colonial Morocco where he was convicted of an assassination plot against French Prime Minister Pierre Mendes-France.
Despite this incident, Denard claimed he was acting in the interests of France or other European powers, and once described himself as "a soldier never an assassin".
His life story is filled with colourful anecdotes.
In 1968 Denard and several hundred fighters tried to invade Katanga, in what is now the Democratic Republic of Congo, by bicycle.
His 1995 coup attempt in the Comoros involved arriving with 30 men in inflatable boats.