Imperial regime of Napoleon III, marked by rapid industrialization, Haussmann's rebuilding of Paris, and an assertive foreign policy (Crimea, Italy, Mexico); collapsed after French defeat and Napoleon III's capture at the Battle of Sedan in the Franco-Prussian War.
Ended by military catastrophe at Sedan (Sept 1870) and the proclamation of the Third Republic in Paris.
Widely used modern scholarly synthesis of the Second Empire.