Florence Cestac did artistic studies in both Rouen and Paris. She co-founded Bonbel, an artist collective in Rouen, and worked for the press group Filipacchi. With Etienne Robial and Denis Ozanne, she opened the bookstore Futuropolis in 1972, and participated two years later in founding the publishing company with the same name. In the same period, she created the comic character 'Harry Mickson', who became Futuropolis' emblem and mascot, and pursued a career in comics in L'Écho des Savanes from 1976.
In addition, Cestac occasionally contributed to Ah Nana!, Métal Hurlant, Charlie Mensuel, Viper, Pilote and Chic. From 1980, she was present in À Suivre, and starting two years later, also in Charlie Mensuel.
In 1989, Cestac created 'Gérard Crétin' in Mikado, and succeeded Sophie Hérout on 'Les Déblok' in Le Journal de Mickey. Furthermore, she illustrated children's books at the publishing house Nathan, and cooperated with Syros and Albin Michel.