Second Empire style, also known as the Napoleon III style, is a highly eclectic style of architecture and decorative arts, which uses elements of many different historical styles, and also made innovative use of modern materials, such as iron frameworks and glass skylights. It flourished in the Second French Empire during the reign of Emperor Napoleon III (1852–1870) and had an important influence on architecture and decoration in the rest of Europe and North America. Major examples of the style include the Opéra Garnier (1862–1871) in Paris by Charles Garnier, the Bibliothèque nationale de France, the Church of Saint Augustine (1860–1871), and the Philadelphia City Hall (1871–1901). The architectural style was closely connected with Haussmann's renovation of Paris carried out during the Second Empire; the new buildings, such as the Opéra, were intended as the focal points of the new boulevards.

The Église Saint-Augustin de Paris is a Catholic church located at 46 boulevard Malesherbes in the 8th arrondissement of Paris. The church was built between 1860 and 1871 by the Paris city chief architect Victor Baltard. It was the first church in Paris to combine a cast-iron frame, fully visible, with stone construction. It was designed to provide a prominent landmark at the junction of two new boulevards built during Haussmann's renovation of Paris under Napoleon III. The closest métro station is Saint-Augustin