French mercenary Bob Denard has failed to attend court as prosecutors appeal against his suspended sentence for a coup attempt in the Comoros Islands.
Denard staged four coups or coup attempts in the Comoros Islands
A lawyer for the 78-year-old, who has Alzheimer's Disease, said his client was unfit for trial.
French prosecutors say the five-year suspended sentence handed down to Denard last year for leading the 1995 coup attempt was inappropriate.
Mr Denard says he was acting on behalf of the French secret services.
Lawyer Elie Hatem said on the eve of the trial that Denard was "physically frail, has kidney problems and his mental faculties are altered".
He said he would ask Ecology Minister Alain Juppe to testify, as he was prime minister when the coup attempt took place in the Comoros.
Denard led 30 men who landed in the Comoros Islands using inflatable boats on 27 September 1995, and captured president Said Mohamed Djohar in the capital Moroni.
French troops quickly ended the coup, in the Indian Ocean archipelago off the coast of East Africa, freeing the president and arresting the mercenaries.
The plot was Denard's fourth and last intervention in the Comoros Islands, which won independence from France in 1975.
A judge accepted the claims of French complicity in the plot when he handed down lighter than expected sentences last year.
The prosecution argues that a suspended sentence should not have been handed down, since Denard had not had been convicted of any offence in the previous five years.
In 1993 he was given a five-year suspended sentence in connection with a failed 1977 coup attempt in Benin.
The latest trial is expected to end on 15 June.