B. de (Berthe de) Buxy

Born Blanche Legrand, this French writer is identified by the Bibliothèque nationale de France as Blanche Legrand (1863–1919) and associated with the pen name Blanche de Buxy / B. de Buxy. A later critical bibliography devoted to her work shows that she built a substantial enough body of fiction to attract dedicated literary study.

Her novels circulated widely enough to remain traceable through major library catalogs and reprints. One of the best-known titles still easy to find is La Demoiselle au bois dormant, a novel of inheritance, family conflict, and social feeling that reflects the tastes of popular French fiction of her era.

The dates in your prompt list 1863–1921, but the clearest library records I found point to 1863–1919 for Blanche Legrand. Because I could not confirm a reliable portrait image from the sources available, I’ve left the profile image blank.