In 1871, Germany was unified. Which French political regime collapsed that same year?

The story behind the answer

The Second Empire collapsed. Napoleon III’s regime crumbled as a direct result of the Franco-Prussian War (1870–71): after his capture at Sedan in September 1870, the empire fell and the Third Republic was proclaimed, with the defeat formalized in 1871 amid the Paris Commune and the Treaty of Frankfurt. Meanwhile, Germany proclaimed its unification as the German Empire at Versailles in January 1871.

Memory tip: Second vs. Second—France’s Second Empire falls just as Germany’s “Second Reich” rises. The July Monarchy had ended in 1848, the Vichy regime belonged to World War II, and the Third Republic actually began in 1870.