(b. 1817, Paris, d. 1885, Paris)
French architect. He won the Prix de Rome in 1840. The young laureate then left Paris and boarded at the Académie de France a Rome. He lived there from 1841 to 1845 and studied the ruins of Antiquity.
Back in France, Théodore Ballu became an assistant to German-born architect Franz Christian Gau (1790-1853) on the Basilique Sainte-Clotilde construction site, then took charge after Gau's death in 1853. From then on, his career was much focused on his preference for religious buildings.
In 1860, he was named chief architect of Parisian buildings related to the religion. He then designed the Église de la Trinité (1861-67), the Saint-Esprit temple on Rue Roquépine, and the churches of Saint-Ambroise (1863-69) and Saint-Joseph (1866-75). He also directed the Saint-Jacques Tower restoration (1854-58) and the construction of the Saint-Denis church in Argenteuil (1866). From 1858 to 1863, Théodore Ballu designed and created the belfry of the Saint-Germain-l'Auxerrois church.