Hidalgo, 54, ran on the Socialist ticket against 40-year-old Nathalie Kosciusko-Morizet, the conservative Union for a Popular Movement candidate, meaning no matter the result, Paris was due to have its first "Madame le Maire."
The Spanish-born Hidalgo had served as deputy mayor of Paris for incumbent Bertrand Delanoe since 2001.
Hidalgo won 54.5 percent of the second-round votes Sunday, over Kosciusko-Morizet's 45.5 percent.
She joins Ana Botella of Madrid, Spain, Patricia de Lille of Cape Town, South Africa, and Carolina Toha, of Santiago, Chile, in an exclusive club of women in charge of major cities around the world.
[Radio France International]