The court sentenced 50-year-old Lotfi Souli to 10 years in jail, of which he must serve at least two-thirds, and his elder son, Karim, 23, to eight years , of which he must serve at least half.
Another son, Mohamed-Amine, who was 15 at the time they left for the Middle East, is to appear before a juvenile court in October.
Lotfi Souli, who is of Tunisian origin, was "extremely dangerous", according to the prosecutor, and the court gave him the highest possible sentence.
But it was relatively lenient on Karim, judging that he acted under his father's influence and had shown progress since his arrest.
Joined Islamic State
The three went to Syria in October 2013 and left in May 2015.
They first joined the Ahrar al-Sham Islamist militia and then moved on to the Islamic State (IS) armed group.
Their claim to have gone there to find a schoolfriend of Karim, Anass Belloum, who was believed to have been killed in fighting at Rakka, failed to convince the court.
Lotfi Souli admitted having put his skills as a telecoms engineer at IS's disposal, claiming he did so to protect his sons, but appears to have been imprisoned by them on suspicion of being a spy after committing a serious error.
Pointing out that IS executed people for far lesser crimes, the prosecution asked what he had promised to do for IS in Europe in exchange for his freedom.
The three returned to France six months before the Paris attacks that claimed 130 lives.
As well as being in possession of large sums of money and manuals on flying planes, handling weapons and bomb-making, they were found to have searched for the Eiffel Tower and Paris's Iéna bridge on Google maps.
Investigators said they took part in military and surveillance training while in Syria.