The three men and one woman had been convicted for their part in the 2010 armed robbery of a car dealership, when they locked up an employee and made off with several vehicles before being caught up in a shootout with police near Paris.
Police officer Jean-Charles Nérin, 52, was shot dead.
He was the only French police officer to be shot by Eta and the last of the 829 to be killed before the organisation renounced violence in 2011.
Eta claimed responsibility for the shooting but claimed the French police fired first.
The court confirmed the sentences of the four people in the dock and banned them all from French territory:
Arkaitz Aguirregabiria del Barrio, 34, who is believed to have been the number two of Eta's military wing, was identified the car showroom employee and accused of starting the shootout, was sentenced to 25 years in jail;
Josu Urbieta Alcorta, 39, who was found to have taken part in the shootout, was jailed for 16 years;
Xabier Goyenechea Iragorri, 37, found guilty of taking part in the robbery, was jailed for 14 years;
Izaskun Lesaca Arguelles, 42, identified as the person who spoke to the showroom employee, was jailed for 14 years;
Two other Eta members refused to exercise their right to appeal, one of them being the last head of the separatist group's military wing, Mikel Carrera Sarobe, alias "Ata".