Paris in French, pronounced /ˈpærɪs/ in English) is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region (or Paris Region, French: Région parisienne). The city of Paris, within its administrative limits largely unchanged since 1860, has an estimated population of 2,193,031 (January 2007), but the Paris metropolitan area has a population of 11,836,970 (January 2007), and is one of the most populated metropolitan areas in Europe.

In 2009 and 2010 Paris was ranked among the three most important and influential cities in the world, among the first three "European cities of the future" – according to research published by the Financial Times –  and among the top ten cities in the world in which to live according to the British review Monocle (June 2010). An important settlement for more than two millennia, Paris is today one of the world's leading business and cultural centres, and its influences in politics, education, entertainment, media, fashion, science, and the arts all contribute to its status as one of the world's major global cities. Paris also ranks among the 10 greenest European cities in 2010

Paris and the Paris Region, with €552.1 bn (US$768.9 bn) in 2009, produces more than a quarter of the gross domestic product (GDP) of France. According to 2007 estimates, the Paris agglomeration is Europe's biggest city economy and the fifth largest in the world. The Paris Region hosts 37 of the Fortune Global 500 companies in several business districts, notably La Défense, the largest dedicated business district in Europe.^[ Paris also hosts many international organizations such as UNESCO, the Organisation for Economic Co-operation and Development (OECD), the International Chamber of Commerce (ICC) and the informal Paris Club. According to the latest survey from Economist Intelligence Unit in 2010, Paris is the world's most expensive city in which to live.

Paris and its region are the most popular tourist destination in the world, with 45 million tourists annually, 27 million of whom are foreign visitors. The city and region contain numerous iconic landmarks — particularly the Eiffel Tower — as well as world-famous institutions and popular parks.

The earliest archaeological signs of permanent settlements in the Paris area date from around 4200 BC. The Parisii, a sub-tribe of the Celtic Senones, inhabited the area near the river Seine from around 250 BC. The Romans conquered the Paris basin in 52 BC, with a permanent settlement by the end of the same century on the Left Bank Sainte Geneviève Hill and the Île de la Cité. The Gallo-Roman town was originally called Lutetia, but later Gallicised to Lutèce. It expanded greatly over the following centuries, becoming a prosperous city with a forum, palaces, baths, temples, theatres, and an amphitheatre.

The collapse of the Roman empire and the 5th-century Germanic invasions sent the city into a period of decline. By 400 AD, Lutèce, largely abandoned by its inhabitants, was little more than a garrison town entrenched into a hastily fortified central island. The city reclaimed its original appellation of "Paris" towards the end of the Roman occupation.

The Paris region was under full control of the Germanic Franks by the late 5th century. The Frankish king Clovis the Frank, the first king of the Merovingian dynasty, made the city his capital from 508. The late 8th century Carolingian dynasty displaced the Frankish capital to Aachen; this period coincided with the beginning of Viking invasions that had spread as far as Paris by the early 9th century. Repeated invasions forced Parisians to build a fortress on the Ile de la Cité; one of the most remarkable Viking raids was on March 28, 845, when Paris was sacked and held ransom, probably by Ragnar Lodbrok, who left only after receiving a large bounty paid by the crown. The weakness of the late Carolingian kings of France led to the gradual rise in power of the Counts of Paris; Odo, Count of Paris was elected king of France by feudal lords, and the end of the Carolingian empire came in 987, when Hugh Capet, count of Paris, was elected king of France. Paris, under the Capetian kings, became a capital once more.

Paris's population was around 200,000 when the Black Death arrived in 1348, killing as many as 800 people a day; and 40,000 died from the plague in 1466. According to Biraben, plague was present in Paris for almost one year out of three in the 16th and 17th centuries to 1670. Paris lost its position as seat of the French realm during occupation of the English-allied Burgundians during the Hundred Years' War, but regained its title when Charles VII of France reclaimed the city from English rule in 1436. Paris from then on became France's capital once again in title, but France's real centre of power would remain in the Loire Valley until King Francis I returned France's crown residences to Paris in 1528.

During the French Wars of Religion, Paris was a stronghold of the Catholic party. In August 1572, under the reign of Charles IX, while many noble Protestants were in Paris on the occasion of the marriage of Henry of Navarre – the future Henry IV – to Margaret of Valois, sister of Charles IX, the St. Bartholomew's Day massacre occurred; begun on 24 August, it lasted several days and spread throughout the country.^[28][29] In 1590 Henry IV unsuccessfully laid siege to the city in the Siege of Paris. During the Fronde, Parisians rose in rebellion and the royal family fled the city (1648). King Louis XIV then moved the royal court permanently to Versailles, a lavish estate on the outskirts of Paris, in 1682. A century later, Paris was the centre stage for the French Revolution, with the Storming of the Bastille on 14 July 1789 and the overthrow of the monarchy in September 1792.