Which European capital city is split into twenty districts called arrondissements?

Paris is the capital and the most populous city of France. It has an area of 105 square kilometres (41 square miles) and a population in 2013 of 2,229,621 within the administrative limits. The city is both a commune and department, and forms the centre and headquarters of the Île-de-France, or Paris Region.

Excluding the outlying parks of Bois de Boulogne and Bois de Vincennes, Paris covers an oval measuring about 87 km2 (34 sq mi) in area, enclosed by the 35 km (22 mi) ring road, the Boulevard Périphérique. The city's last major annexation of outlying territories in 1860 not only gave it its modern form but also created the 20 clockwise-spiralling arrondissements (municipal boroughs).

The city of Paris is divided into twenty arrondissements municipaux, administrative districts, more simply referred to as arrondissements. These are not to be confused with departmental arrondissements, which subdivide the 101 French départements. The word "arrondissement", when applied to Paris, refers almost always to the municipal arrondissements. The number of the arrondissement is indicated by the last two digits in most Parisian postal codes (75001 up to 75020).