Investigators initially suspected terrorists but quickly uncovered a trail of clues that lead directly to the French secret service.
Besson is an EP alongside film producer and wife Virginie Besson-Silla.
Tatiana Jezierski will join later this month from creative agency Mother, where she was Strategy Director.
Rainbow WarriorDocsville
ITVs in-house agency was set up to promote the pubcasters content and delivers thousands of campaigns per year.
