[3] De Flandreysy began her career as a contributor to La Revue Dauphinoise.

For example, her 1903 book entitled La Vénus d'Arles et le Museon Arlaten was prefaced by Frédéric Mistral,[5] while her 1924 book entitled La maison de Baroncelli en Italie du Xe au XVe siècle was prefaced by Charles Maurras.

[3] With Jules Charles-Roux, she helped Frédéric Mistral establish a gallery with statues from the Antiquity found on the grounds of the Museon Arlaten.

[11] De Flandreysy purchased the Palais du Roure, a hôtel particulier in Avignon in 1918.

[3] De Flandreysy married Émile Espérandieu, an archaeologist and epigrapher, on 8 September 1936.