The Barrière du Trône or Barrière de Vincennes was a gate at the former Wall of the Farmers-General (Mur des Fermiers généraux). The gate facilitated the collection of the octroi, or tax on goods entering the capital and was considered a royal entrance. Built in 1787 on the plans of the architect Claude Nicolas Ledoux , it included two sentry boxes framing a grid of about 60 meters and serving as a pedestal with two columns of 28 meters high. Architect Claude Nicolas Ledoux designed the wall's 62 toll barriers in a neo-classical or even classical style. It now stands at the Place de la Nation. (wikipedia.org)