In What Context Was the Third Republic Proclaimed?

The Third Republic was the political regime that succeeded the Second Empire. It was proclaimed on September 4, 1870

Barricade at the corner of boulevards Voltaire and Richard-Lenoir during the Paris Commune of 1871
Barricade at the corner of boulevards Voltaire and Richard-Lenoir during the Paris Commune of 1871. Photograph presented at the "La Commune 1871, Paris capitale insurgée" exhibition at Paris City Hall on April 5, 2011. Image: Wikimedia Commons