Fourteen people are on trial that started in France on Wednesday over the 2015 massacre at the office of the satirical magazine Charlie Hebdo in Paris.
While 11 of the defendants were present in the courtroom, three were being tried in absentia, the BBC reported.
The 14 suspects are accused of helping the the two Islamist attackers who shot dead 12 people, including the magazine's editor Stephane Charbonnier on January 7, 2015.
In a related attack, a policewoman was shot dead by a third gunman who also attacked a Jewish supermarket where he killed three customers and an employee.
In total, a total of 17 people were killed in a period of just three days.
All the gunmen were killed by security forces.
The trial had been delayed by almost four months due to the ongoing coronavirus pandemic.
In March, the presiding judge said France's lockdown measures had made it impossible to bring together "all the parties, witnesses and experts under the necessary sanitary conditions".
There are about 200 plaintiffs in the trial and survivors of the attacks are expected to testify in the trial expected to continue until November.