Periphery (France)

A periphery, (Fr: couronne) is an INSEE (French demographic statistics institution) statistical area designating a commuter belt around an urban unit (Fr: unité urbaine). Together these complete the INSEE urban area statistical area.

Based on France's commune system (interlocking administrative subdivisions often comparable to civil parishes, towns or cities), a commune is considered part of a couronne when
 * 1) it is not densely constructed enough or is too isolated to be part of any unité urbaine (or "pôle urbain" if it is the core of the agglomeration), and
 * 2) at least 40% of its population commutes to workplaces in a unité urbaine or pôle urbain, or to another commune connected to a unité urbaine through the same criteria.