Léonie Chaptal was a wealthy heiress. She had an excellent education that she completed on her own initiative. Between 30 and 40 years old, she founded and managed health charities in a popular and disadvantaged district of Paris. She was interested in all the aspects of life, from birth to death. Though fervent, she lived as an officially laic liberal catholic woman. Her noticeable competency brought her to sit at the Conseil supérieur de l'Assistance publique (Welfare services), where some national decisions of public health were made. Her action against tuberculosis was acknowledged worldwide. She opened a training school in nursing care from 1905, and participated to the national and international debates on this theme of training. 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 as the obtaining of a nursing diploma after two years of studies at school. But to practice, this diploma was not required, what depreciated the function. After having created the French association ANIDEF, she became the president of the International Council of Nurses. Between the wars, the practice of the nursing profession was far below Léonie's aspiration, who was torn between her opponents: some Republicans little likely to favour women's work and some Catholics attached to claim their faith.