Paris-based agency conglomerates Havas and Publicis are mourning the loss of six staffers in the Nov. 13 attacks that rocked the City of Lights.

Havas CEO Yannick Bollore said the group lost four "family members," referring to the fallen staffers by their first names -- Claire (Havas Media), Francois Xavier (Adcity), Christophe (Havas Life) and photographer Eric. Francois Xavier is said to be Francois Xavier Prevost, age 29.

Fabrice Dubois, 46, a staffer of Publicis Conseil and a father of two, was also killed in the attacks. The firm said via Facebook that "All the agency's upset. He was a very great man, in every sense of the word." Yannick Minivielle, creative director for Publicis RED, also died from injuries in the attacks on the Eagles of Death Metal concert at Paris' Bataclan concert hall.

Publicis chair Maurice Levy said the attacks "brought darkness upon many families," noting "our professional family was not saved from this blind, murderous madness."