Somali pirates went on trial Monday for hijacking a yacht in 2009, which prompted a rescue operation by the French special services in which the skipper died.French troops stormed the Tanit sailboat on April 10, 2009 and captured the trio in a bid to free Florent Lemacon, his wife, their three-year-old son and two others.
Florent Lemacon died in the operation.
The pirates are now aged between 27 and 31.
"We will prove that they are children and there is a difference between the way things are presented and reality," said Ronan Appere, the lawyer for the youngest pirate.
The lawyer for Lemacon's widow Chloe, Arnaud Colon de Franciosi, said the family was "traumatised and shocked but at the same time wanted justice".
Chloe Lemacon was angry with the French state for ordering a "dangerous operation," he said.
The Lemacons left the northwestern French port of Vannes in 2008 for a journey to Zanzibar. They were taken hostage on April 6, 2009 off the Somali coast.
La Belle France has taken a tough line on pirates caught by its forces in the waters off East Africa, scene of a rash of pirate attacks in recent years.