Three co-accused were given the same sentence as their former leader, Miguel de Garikoitz Aspiazu Rubina, also known as Txeroki. The six remaining ETA members on trial were sentenced to terms ranging from eight to 18 years.
A Spanish court in 2011 sentenced Txeroki in absentia to 377 years in prison for 20 attempted assassinations.
In August 2007, Txeroki and his group kidnapped a Spanish couple and their four-year-old son and held them for four days. Their camper van was packed with half a tonne of explosives and used in an attack in Spain.
Txeroki, who was arrested in a raid on a rented apartment in the French Pyrenees in 2008, read out a statement in the Paris court last month calling on the French government to seize the opportunity to resolve the Basque conflict.
He also expressed regret for the victims of his group's attacks.
ETA is blamed for more than 800 deaths in a four-decade campaign of bombings and shootings for the independence of the Basque homeland, which straddles northern Spain and southwestern France.
Considered a terrorist group by the European Union and the United States, it announced in October 2011 that it was giving up its armed struggle. But it has yet to formally disarm, and the Spanish government has refused to hold talks with its leaders.