Paris is the capital and most populous city of France, with a population of 2,148,271 residents in an area of 105 square kilometres. Since the 17th century, Paris has been one of Europe's major centres of finance, diplomacy, commerce, fashion, science and arts. The City of Paris is the centre and seat of government of the Île-de-France, or Paris Region, which has an estimated official 2020 population of 12,278,210, or about 18 percent of the population of France. The Paris Region had a GDP of €709 billion in 2017. According to the Economist Intelligence Unit Worldwide Cost of Living Survey in 2018, Paris was the second most expensive city in the world, after Singapore, and ahead of Zürich, Hong Kong, Oslo and Geneva. Another source ranked Paris as most expensive, on a par with Singapore and Hong Kong, in 2018.
The city is a major railway, highway and air-transport hub served by two international airports: Paris-Charles de Gaulle and Paris-Orly. Opened in 1900, the city's subway system, the Paris Métro, serves 5.23 million passengers daily; it is the second busiest metro system in Europe after the Moscow Metro.