ティエールの城壁
The French war department had completed the Thiers wallincluding fortifications, a dry moat, a "Rue Militaire" and a large bermaround 1840. In 1859, the military engineering service gave conditional control to the Paris city council. The expansion of the land area of Paris in 1860, by annexing bordering communities, created a situation where everything within the Thiers wall was Paris and everything without was not. The Thiers wall, with its accompanying berm and moat, led to a profound disruption and complication of the synergistic relationship between Paris and its suburbs.