The two other attackers had already been identified as French nationals Omar Ismail Mostefai and Samy Amimour.
Two of the gunmen, who killed 90 people at the Bataclan, blew themselves up with suicide belts, while the other was shot by police when they stormed the venue.
Aggad was identified at the end of last week because his DNA matched that of members of his family.
Investigators believe that two of the men from Strasbourg who went to Syria, Mourad and Yassine Boudjellal, were killed fighting in the ranks of what was to become the Islamic State (IS) armed group.
While Aggad stayed on, the others started to return to France in February 2014.
Seven men were arrested in Strasbourg in May last year and are still in custody on terrorist charges.
Police suspect that the group that went to Syria were recruited by Mourad Farès, 31, who was known to French intelligence as an IS recruiter through social media and the internet.
He, too, is in custody after being arrested in August 2014 in Turkey and handed over to the French authorities.
Interior Minister Bernard Cazeneuve has described him as a "particularly dangerous individual".