The men were arrested after a deadly raid in the Belgian town of Verviers in January 2015 which exposed an alleged plan to kill police officers.
The Verviers plot "was the rough draft of Paris," prosecutor Bernard Michel told the court in Brussels, adding that the accused were under the orders of Abdelhamid Abaaoud, the ringleader of the deadly November attacks in the French capital.
Abaaoud was killed in a French police raid days after the November 13 Paris gun and bombing attacks. He also had close links to the cell behind the March 22 Brussels airport and metro attacks.
He denies the charges.
Killed in the raid were Sofiane Amghar and Khalid Ben Larbi who went to Syria to join Islamic State in April 2014. The two then slipped back into Belgium to the Verviers hideout.
Prosecutors demanded the longest sentence of 18 years for Mohamed Arshad, who had told the court he acted on instructions from Abaaoud to buy walkie-talkies, ingredients for explosives and rent two vehicles and a flat in Verviers.
The documents were provided by small-time criminal Souhaib El Abdi, who prosecutors said should be jailed for 16 years.
The prosecution asked for 10 years in jail for Omar Damache, an Algerian who was arrested at an address in Athens where police believe they had zeroed in on Abaaoud. He was later extradited to Belgium.
In all, seven men were on trial, with an additional nine suspects who are still at large tried in their absence.
