France (French: [fs] ), officially the French Republic (French: Rpublique franaise), is a transcontinental country spanning Western Europe and overseas regions and territories in South America and the Atlantic, Pacific and Indian Oceans. Including all of its territories, France has twelve time zones, the most of any country. Its metropolitan area extends from the Rhine to the Atlantic Ocean and from the Mediterranean Sea to the English Channel and the North Sea, overseas territories include French Guiana in South America, Saint Pierre and Miquelon in the North Atlantic, the French West Indies, and several islands in Oceania and the Indian Ocean. Due to its several coastal territories, France has the largest exclusive economic zone in the world. France borders Belgium, Luxembourg, Germany, Switzerland, Monaco, Italy, Andorra and Spain in Europe, as well as the Netherlands, Suriname and Brazil in the Americas. Its eighteen integral regions (five of which are overseas) span a combined area of 643, 801 km2 (248, 573 sq mi) and over 67 million people (as of May 2021). France is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre, other major urban areas include Lyon, Marseille, Toulouse, Bordeaux, Lille and Nice. Inhabited since the Palaeolithic era, the territory of Metropolitan France was settled by Celtic tribes known as Gauls during the Iron Age. Rome annexed the area in 51 BC, leading to a distinct Gallo-Roman culture that laid the foundation of the French language. The Germanic Franks arrived in 476 and formed the Kingdom of Francia, which became the heartland of the Carolingian Empire.