In 2003, the City of Besançon launched reflection on the inclusion of the major sites of Vauban as a UNESCO World Heritage Site. Since March 2005, the association of Cities "Network of Major Sites of Vauban" has relayed the momentum and worked intensely to put together a registration file that meets the requirements and criteria of the French State and Unesco.
It is the series as such, and not the individual sites, that represents Outstanding Universal Value.
Each fortified site presents a facet of Vauban's work, complementary to the others. The choice of sites is based on a scientific basis and is based on the criteria of the World Heritage Committee: representativeness of the evolution of the Vauban defense system, a type of fortification and a type of geographical site (edge sea, plain, mountain), state of conservation of fortifications and authenticity, landscape environment, existing development and protection policies.