The Second Empire (1852-1870) was the regime of Napoleon III. Authoritarian then liberal, it transformed Paris under Haussmann and boosted industry. The defeat of Sedan in 1870 brought the Empire to an end. Restored on 2 December 1852 after a plebiscite, it took France into the Crimean War, Italian unification and the Mexican expedition. Napoleon III was taken prisoner at Sedan on 2 September 1870; the Republic was proclaimed in Paris two days later.