Paris is the most populous urban area in the European Union, but the strict definition of the administrative boundaries of the city of Paris results in a much lower area. With a population of 14 million, London is the largest city in the European Union and Europe. Istanbul is sometimes not included in the list of the most populated cities in Europe, since technically the city stretches on both sides of the Europe-Asia border. With so many fluctuating figures based on so many different definitions, it is probably more useful to conclude by dividing European cities into three general classes.
Istanbul in Turkey and Moscow in Russia are by far the largest cities on the European continent (although some may argue whether they are culturally European and none of them are part of the European Union). In recent years, the population of this cosmopolitan city is growing much faster than ever due to the incessant influx of workers from all over Europe. Today, this city, like most cities in Eastern Europe, is modernizing very rapidly and is trying to melt the gap in economic terms with the developed urban centers of Western Europe. So let's include European Turkey, give Istanbul the benefit of the doubt, and extend Europe to the Ural Mountains in Russia.
Europe is also home to many much smaller, but still historically and culturally important cities. There is the EU, the Schengen area, the Customs Union, the EEA, the continent and then the sticky issue of Europe itself. It is the eighth largest agglomeration in Europe, the fifth in the European Union and the second largest in Spain. This is partly because some European countries are relatively small and others have several major cities instead of one large capital.
However, these cities are definitely outliers, and statistics show that populations between one and three million are more typical of many major European cities, such as Rome (2.3 million), Paris (2.1 million) and Vienna (1.6 million). Paris is the most populous urban area in the European Union, but the strict definition of the administrative boundaries of the city of Paris results in a much lower population than shown in the table.