After studying Fine Arts in Saint-Étienne for eight years, Chantal Montellier started educating graphics in 1969. That same year, she took on painting and started making illustrations for leftwing publications like Le Combat Syndicaliste, L'Humanité Dimanche, France Nouvelle, La Nouvelle Critique, Révolution, Maintenant, L'Autre Journal and Le Matin de Paris.
In 1974 Montellier started doing comics for Métal Hurlant, Canard Sauvage and the female magazine Ah! Nana. In the latter, she published the first pages of her 'Andy's Gang' series. The series was continued in Métal Hurlant from 1978. Her short stories for this magazine were collected in several albums by Humanoïdes Associés, like '1996', 'Shelter Lectures', 'Wonder City', etc.
In addition, she was contributing to À Suivre ('Hôpital Bellevue', 'Virginia Woolf', etc.) and she created several albums for the publishers Kesselring ('Rêves du Fou', 'Le Sang de la Commune') and Futuropolis ('La Toilette', 'Un Deuil Blanc'). In 1989 Montellier created 'Julie Bristol' in À Suivre, which she continued in a series of albums published by Casterman and Dargaud. Also for Dargaud, she made 'Voyages au Bout de la Crise' and 'Paris sur Sang: Mystère au Père-Lachaise'. In the 2000s, Montellier has worked for the publishing field, done illustration work and contributed stories to Psikopat. Chantal Montellier uses an esthetic photographic style, which shows traces of an early Jacques Tardi.