Daughter of Jeanne de Balidard and of Charles-Gabriel de Messey, baron de Braux- Le-Chatel, captain of cavalry and chevalier de Saint-Louis.

Known for her sharp tongue. Franklin affectionately called her “la petite femme de poche.” She had printed a four-page brochure entitled, Proposition d’une femme citoyenne, pour établir les moyens de remédier à toutes les calamités qui environnent la France (1789).

Married one of Franklin’s close friends and scientific collaborators, Jean-Baptiste Le Roy, a member of the Academy of Sciences who conducted experiments on electricity (1771).