Marthe de Florian was born in the 18th arrondissement of Paris, eldest daughter of Jean Beaugiron (1837-1875) and Henriette Eloïse Bara (1844-1891), who had married in 1864.
At the age of 19, on 7 April 1884, de Florian gave birth to a second son also called Henri Beaugiron (1884-1966), who was born at 100 Rue Saint-Lazare.