Léonie Chaptal was a wealthy heiress. She had an excellent education, which she completed on her own initiative. Between the ages of thirty and forty, she founded and managed health charities in a disadvantaged, working-class district of Paris. She was interested in all aspects of life, from birth to death. Though fervent, she lived as an officially secular liberal Catholic woman. Her remarkable skills brought her to sit at the Conseil Supérieur de l’Assistance Publique (Welfare services), where national decisions about public health were made. Her action against tuberculosis was acknowledged worldwide. She opened a training school in nursing from 1905, and participated to the national and international debates on such education. During the Great War, she was particularly active. In the 1920s, she presented a report on nursing education which immediately gave rise to the drafting of a decree which structured nursing schools and programs in France, as well a nursing diploma obtained after two years of study. But this diploma was not required to practice, which made it less useful. After having created the French association ANIDEF, she became the president of the International Council of Nurses. Between the wars, the practice of nursing was far below Léonie’s aspiration, caught as she was between her opponents: Republicans unfavorable to women’s work, and Catholics attached to their faith.