Apart from their role as organizational units in relation to certain aspects of the administration of public services and justice, the chief purpose of the cantons today is to serve as constituencies for the election of members of the representative assemblies established in each of France's territorial departments (departmental councils, formerly general councils).

For statistical (INSEE) purposes, the twenty arrondissements of Paris – the administrative subdivisions of that city – are sometimes considered cantons, but they serve no greater electoral function.

[2] Cantons also form legal districts, as seats of Tribunaux d'instance (TI) or Courts of First Instance.

The number of cantons was then drastically reduced (between 30 and 50 units) by the Loi du 8 pluviôse an IX (28 January 1801), or the "Law for the Reduction of the Number of District Courts", or Loi portant réduction du nombre de justices de paix in French.

The département lists, once approved by the government, were published in the Bulletin des lois in 1801 and 1802; these lists were the basis of the administrative divisions of France from then until 2015, although cantons with small populations were eliminated and new cantons created in areas of strong demographic growth.