“We will never lie down. We will never give up,” wrote its director Laurent “Riss” Sourisseau in an editorial to go with the republication of the cartoons in its latest edition.
Twelve people, including some of France's most celebrated cartoonists, were killed on January 7th, 2015, when brothers Said and Cherif Kouachi went on a gun rampage at the paper's offices.
The trial had been delayed several months due to the coronavirus epidemic.
The court in Paris will sit until November 10th and, in a first for a terror trial, proceedings will be filmed for archival purposes given public interest.
Of the 14 suspects, three are being tried in absentia: Hayat Boumedienne, the partner of Coulibaly, and the Belhoucine brothers Mohamed and Mehdi.
All three are believed to have travelled to the area of northern Syria and Iraq that at the time was under IS control.
Reports have suggested they are dead but this has never been confirmed and they remain subject to arrest warrants.
Facing the most serious charge of complicity in terror and a maximum sentence of life in jail, are Mohamed Belhoucine, the elder of the two brothers, and Ali Riza Polat, 35, a French citizen of Turkish origin who will be the most prominent of the accused in the dock.
Polat, seen as close to Coulibaly, is suspected of having played a central role in preparing the attacks, notably by helping to build up the arsenal used by the three perpetrators.
He is also accused of providing help “at all stages of the preparation”.
Just after the attacks, he repeatedly tried to leave France for Syria but has been held since March 2015.
Mohamed Belhoucine is accused of being the ideological mentor of Coulibaly after meeting him in jail, opening up channels of communication for him to IS and writing the oath of allegiance that Coulibaly made to the group.
Most of the other suspects are on trial for association with a terror group, a crime that comes with a jail sentence of up to 20 years.