I am writing in English today, as I hope to reach a larger audience. I would like to rectify two mistakes which I am often encountering about Clémence de Grandval (1828-1907), one of the most important women composers of the end of the 19th century.
She sometimes appears as "Marie Grandval" or "Marie de Grandval", and she is credited for having used multiple pseudonyms.
The first point: here is an illustration published at the time of the creation of her opera Mazeppa in Bordeaux in 1892. The C. stands for her third given name: she was christened Marie Félicie Clémence but always used Clémence.

This is testified by her publications, at first under Clémence de Reiset, her maiden name, and C. de Grandval after her marriage in 1851; and on a more personal note by her letters, signed C. de Grandval, for example those to Camille Saint-Saëns (you can check the collection kept at the Bibliothèque Nationale de France).
By the way, some people think that the C. stands for "Comtesse". No, she was a "Vicomtesse", having married the Vicomte Enlart de Grandval. Some publications use the title.
Now to the multiple pseudonyms. There are only two, Caroline Blangy and Clémence Valgrand. The first one was used when she had her comic opera Le Sou de Lise premiered in Paris in 1860. The second one was used for her comic opera Les Fiancés de Rosa premiered in Paris in 1863. Both works were published under the pseudonyms. It is interesting to see that CJémence de Grandval was not hiding her gender, but her aristocratic origins, which proved a big obstacle to her career, as she was considered by many as an amateur, despite the high quality of her music.