The Paris aire urbaine's territory expands at each population census as new communes (municipalities) surrounding Paris become included in the aire urbaine when they meet the 40% commuter threshold required to be considered part of the aire urbaine. At the 1968 census, the earliest date for which population figures were retrospectively computed for French aire urbaines, the Paris aire urbaine had 8,368,459 inhabitants in its then limits which only encompassed the central area of Île-de-France. At the 1999 census the Paris aire urbaine was by then slightly larger than Île-de-France and had 11,174,743 inhabitants. Its population is now estimated to be nearly 12 million in its 1999 limits. INSEE should revise the limits of the Paris aire urbaine when the results of the 2006 population census are published in the coming years. Map of the 36,568 communes of metropolitan France. ...