A French court has convicted seven young men who returned from weeks among the ranks of Islamic State extremists in Syria, including the brother of one of the suicide attackers who targeted Paris in November.

The defendants, aged 24 to 27, were sentenced Wednesday to prison terms ranging from six to nine years for taking part in a group recruiting French jihadis, for joining a "terrorist group" in Syria in 2013-2014, namely IS, and for participating in military training and other activities.

Karim Mohamed-Aggad, brother of one of the extremists who attacked the Bataclan concert hall Nov. 13, received a 9-year term, the harshest penalty among the seven defendants.

The prosecutor said he was one of the ringleaders. Mohamed-Aggad claimed he went to Syria only for humanitarian purposes.