Seven men have gone on trial in Paris accused of recruiting fighters for the so-called Islamic State (IS) extremist group in Syria.
One of the suspects, Salim Benghalem, is being tried in absentia as he is thought to be in Syria.
He is thought to be one of the highest-ranking foreign fighters in the organisation.
It is the first such trial since 130 people died in attacks in Paris on 13 November which IS says it carried out.
Salim Benghalem has been linked to an extremist cell in Paris which is also believed to be connected with Cherif Kouachi, who along with his brother killed 12 people in January at the offices of the satirical magazine Charlie Hebdo.
His wife, who has left Syria, has told investigators that he said he would only return to France to launch attacks.
Benghalem has appeared in Islamic State propaganda material and was reportedly the target of a French airstrike in Raqqa.
The US has accused Benghalem of carrying out executions for the group.
Benghalem is reported to have fought for the al-Qaeda affiliated al-Nusra Front before joining IS.
Five of the other suspects on trial are also accused of having gone to Syria to fight, with only one remaining in France.
A lawyer for one of the other men on trial sid he feared his client would not get a fair trial.
“There is a context with the events of the past days that will no doubt influence this long hearing and maybe will have an impact on the serenity required for a ruling,” lawyer Xavier Nogueras told AP.