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 larger French departments. The number of the arrondissement is indicated by the last two digits in most Parisian postal codes (75001 up to 75020). In addition to their number, each arrondissement also has a name, often for a local monument. For example, the 5th arrondissement is also called "Panthéon" in reference to the eponymous building. The first four arrondissements have a shared administration, called Paris Centre. Description The twenty arrondissements are arranged in the form of a clockwise spiral (often likened to a snail shell), starting from the middle of the city, with the first on the Right Bank (north bank) of the Seine. In French, notably on street signs, the number is often given in Roman numerals. For example, the Eiffel Tower belongs to the VIIe arrondissement while Gare de l'Est is in the Xe arrondissement. In daily speech, people use only the ordinal number corresponding to the arrondissement, e.g. "Elle habite dans le sixième", "She lives in the 6th (arrondissement)". Due to suburbanization, the population of Paris has gradually shifted outward, with only two arrondissements still growing. Governance Uniquely among French cities, Paris is both a municipality (commune) and a department (département). Under the PLM Law (Loi PLM) of 1982, which redefined the governance of Paris, Lyon, and Marseille (hence the PLM acronym), there are both a city council called the Council of Paris and 20 arrondissement councils in Paris. The PLM Law also set limits to the prerogatives of the mayor of Paris, who has to deal with the powers granted to the prefect of police on security issues. The 20 arrondissement councils (conseils d'arrondissement) are similar in operation to a municipal council (conseil municipal) but with very few powers. Its members are elected at municipal elections in the same way as in municipalities with more than 3,500 inhabitants. Each arrondissement council is made up of 2/3 members elected specifically as arrondissement councillors, while Council of Paris members representing the arrondissement also sit ex officio on their local arrondissement council. For example, the council of the 19th arrondissement has 42 members, of which 28 are conseillers d'arrondissement who only sit on the arrondissement council, while 14 are conseillers de Paris who also sit on the city