Paris is the capital and largest city of France. It is situated on the river Seine, in northern France, at the heart of the Île-de-France region (or Paris Region, French: Région parisienne). As of January 2009 the city of Paris, within its administrative limits (the 20 arrondissements) largely unchanged since 1860, has an estimated population of 2,234,105 and a metropolitan population of 12,161,542, and is one of the most populated metropolitan areas in Europe.Paris was the largest city in the Western world for about 1,000 years, prior to the 19th century, and may have been the largest in the entire world between the 16th and 19th centuries.