Abdelhakim Dekhar, now 52, was arrested in November 2013 following a major manhunt after he broke into the headquarters of the BFMTV channel.
There, he threatened journalist Philippe Antoine with a shotgun, and said: "Next time, I won't miss."
Three days later, still on the run, he managed to stage a shooting attack at the offices of left-wing newspaper Liberation, also in Paris, that left a photographer's assistant seriously hurt.
There was also a separate incident where shots were fired at the headquarters of the Societe Generale bank.
The court found him guilty of attempted murder of Philippe Antoine, now chief editor at BFMTV, and Cesar Sebastien, the wounded photographer's assistant at Liberation.
Prosecutor Bernard Farret had argued that "spite" had been Dekhar's main motive, adding that the shooter harboured "resentment against society, the state and capitalism".
Dekhar, sentenced on Friday, was considering filing an appeal, his lawyer Hugo Levy said.
Of the total, Dekhar will only be eligible for parole once he has served two thirds of his sentence.
During his trial, Dekhar repeatedly evoked political arguments, raising topics such as France's colonisation of Algeria and social problems in the French suburbs.
He had also claimed he was suicidal and "desperate" for the police to end his life.
Dekhar had been jailed in the 1990s for his role in a "Bonnie-and-Clyde" style multiple murder and left rambling letters denouncing conspiracies and media manipulation.
The case predated the January 2015 jihadist attack on the premises of satirical magazine Charlie Hebdo, which left 12 people dead.
On November 13 that year, gunmen and suicide bombers left 130 people dead in a coordinated attack targeting several Paris locations including a concert hall.
The attacks profoundly shook France, triggering a state of emergency that was lifted only this month after President Emmanuel Macron signed a controversial new anti-terror law.