Salah Abdeslam, the only surviving member of the terrorist cell that killed 130 people in the French capital in 2015 was given the so-called incompressible "real life" prison sentence of 30 years for his role in the attacks.
Six other defendants -- five of which were tried in absentia and considered to be dead -- were also given whole-life terms. The remaining 13 defendants out of 20 were also jailed for between two and 30 years.
The ruling aligns with France's National Anti-Terrorism Prosecutor's Office (PNAT), which had requested a "perpétuité réelle" ("real life") sentence for Abdeslam -- the heaviest penalty in the country's criminal code.
But multiple social media users have expressed their disdain that the main defendant could walk free after three decades behind bars.
"Sentenced to life imprisonment which lasts only 30 years and then Salah Abdeslam will be released for good behaviour," one Twitter user questioned.
What is an 'incompressible' life sentence?
The PNAT has argued that Abdeslam was a "key actor" in the attacks, had remained faithful to his ideology and had never expressed the "slightest remorse".
Prosecutors requested the rare life sentence punishment due to the "immense seriousness" of the 32-year-old's actions.
Life imprisonment is the harshest sentence in the French penal code and such a penalty makes the possibility of a reduction of the time served very slim.
Unlike other life sentences in France, which come with an option for parole after the prisoner serves 18 to 22 years -- known as a "safety period" -- certain crimes, such as terrorism causing death, invoke the incompressible sentence of at least 30 years before the convicted person cannot benefit from parole or conditional release.
After the period has passed, they can in theory ask the court to reconsider this decision and modify the sentence each year.
However, this does not mean that the convict is automatically released. In some cases, an incompressible life sentence means there is no possibility of parole at all.
How could a prisoner be released after 30 years?
In order to be eligible for release after a life sentence, a convicted person in France must fulfil three criteria.
They first must show serious signs of social rehabilitation and integration and, secondly, they must not be considered a "serious disturbance" to society.
And thirdly, the court must ask the opinion of the victims of the crime before a convicted prisoner can be released, once a panel of experts has carried out a psychiatric assessment.
Due to the seriousness of the Paris terror attacks and the emotion behind the trial, it is therefore highly unlikely that all victims will approve of Abdeslam's freedom.
During the trial, the 32-year-old had maintained that he was "not a murderer, not a killer".
This will be the first time that an incompressible life sentence will be handed down for terrorist crimes in the country.
Such a verdict has only been given four times in modern French history for cases involving murders, rape, or torture.
These cases were Pierre Bodein (known as "Pierrot le fou") in 2007, Michel Fourniret -- who has since died in prison -- in 2008, Nicolas Blondiau in 2013 and Yannick Luende Bothelo in 2016.
The European Court of Human Rights ruled in 2014 that such a "real life" sentence did not violate human rights provisions, as it offered hope, no matter how small, that a prisoner would eventually be released.