Region: Île-de-France covers an area of approximately 12011 km² and has a population of approximately 12 million people. The 3 largest cities in Île-de-France according to population are Paris with approximately 2240621, Boulogne-Billancourt with approximately 119808 and Montreuil with approximately 103192 inhabitants. Most of the fairs in Île-de-France take place in Paris.