Three of the men and one woman were referred to a court in Paris Thursday after their arrests earlier this week, Radio France Internationale reported Friday.
Authorities said they believe the group organized training in and around Paris and contacted French "facilitators," who arranged for potential militant fighters to travel to Syria to fight in combat zones.
Investigators said they think some of the group had ties to the al-Qaida-linked Al-Nusra Front, a member of the Syrian opposition, and were investigating the group's relationship with a man from Lyon who is sometimes called the "emir" of French fighters in Syria.
Separately, two women and a man were charged in a case involving a 15-year-old girl from Avignon who was stopped at an airport apparently on her way to Syria via Turkey, RFI said.
In Spain, security forces announced they broke up a major Spanish-and-Moroccan network that has sent militants to Syria, RFI said.
Notable deaths of 2014 [PHOTOS]