The "Cannes-Torcy cell", named after the towns where its members were based, was accused of having planned several other attacks as well as seeking to join jihadist ranks in Syria before the network was dismantled in 2012. Eighteen men were found guilty and two were acquitted.
The verdict comes after a wave of jihadist assaults in France that have left more than 230 people dead since 2015 and an attack this week on a police van by a car laden with weapons and gas canisters on Paris's Champs-Elysees.
Analysts say the Cannes-Torcy network signalled a historic shift in France's struggle against terrorism, to battling mass attacks by Islamic radicals inspired, or even guided, by foreigners.
During the hearing at a special anti-terror tribunal in Paris, the cell was described as "the missing link" between the self-proclaimed Al-Qaeda militant Mohamed Merah -- who murdered three Jewish children and a teacher in an attack at their school in the southwestern city of Toulouse in 2012 -- and the network that hit the Bataclan concert hall in 2015, killing 130 people.
The prosecution demanded "exemplary punishments" for the cell, headed by Jeremie Louis-Sidney and described as a violent leader with a "boiling" hatred for Jews.
Police arrested two members of the network while investigating the grenade attack on a Jewish grocery in the Paris suburb of Sarcelles in September 2012.
Two masked men threw a grenade into the shop, injuring one person, but the fact that it rolled under a trolley prevented more casualties.
In the absence of Louis-Sydney, who was killed when police tried to arrest him in the eastern city of Strasbourg, the longest sentence was given to Jeremy Bailly, found guilty of throwing the grenade.
Kevin Phan, the group's driver during the attack, was sentenced to 18 years in jail.
Sentences of 14 to 20 years' imprisonment were given to gang members who had travelled to Syria, including Ibrahim Boudina, who spent sixteen months in Syria and was accused of "returning to commit an attack" on the Cote d'Azur.
Lawyers said the court had noted the diverse profiles of the twenty men, some of whom were from well-to-do families, and came from Algeria, Laos and France. Half were converts to Islam.