The defendants were handed prison sentences ranging from two to eighteen years.
Eight people have been convicted for their roles in the 2016 Nice truck attack that killed 86 people and left 400 others injured.
Seven men and one woman were all found guilty of conspiring to orchestrate the attack, the second deadliest on French soil.
The truck's driver -- a 31-year-old Tunisian -- had deliberately crashed into crowds watching the Bastille Day fireworks on 14 July 2016, before being shot dead by police.
Among the victims, 33 were foreign citizens and 15 were children.
A Paris court sentenced the eight defendants to between two and eighteen years in prison.
Mohamed Ghraeib and Chokri Chafroud -- who had “an intense relationship” with the attacker Mohamed Lahouaiej-Bouhlel -- were both convicted of terror charges and handed the longest sentences.
Another man, Ramzi Arefa, was convicted of selling Lahouaiej-Bouhlel a weapon and received a 12-year prison sentence.
Two of those on trial are French-Tunisian dual nationals, while two others are Tunisian and four are from Albania. One was tried in absentia, while a ninth suspect committed suicide in detention in June 2018.
Prosecutors had also acknowledged that not all of the defendants had known about the attacker's plans. The verdict can be appealed.
While investigators found Lahouaiej-Bouhlel had voiced support for the so-called Islamic State (IS) group, they found no clear proof of his links to the terrorist organisation.
The court's decision has been welcomed by survivors of the attack and victims' relatives. More than 2,400 people were listed as civil parties in the trial.