In 1999 the part of the population of the Paris metropolitan area living in Ile de France represented 98 996 of its total population The same year the part of the population of Ile de France living in the Paris metropolitan area represented 97 023 of its total population In 1999 the demographical difference between Ile de France and the Paris metropolitan area was about 2 There s nothing illegitimate in considering the Ile de France GDP as an estimation of the Paris metropolitan area Actually the conversion from Euros to US dollars leads to a much stronger approximation of that figure knowing that both currencies have fluctuated in a margin of 10 in the last 12 months You see ThePromenader your behaviour is in here exactly the one I can t stand anymore It consists in finding a little trick to make disappear a valuable information for a reason I fail to understand The GDP of Ile de France is definitly a legitimate estimation of the Paris metropolitan area which is perfectly legitimate to mention in the article about the economy of Paris Normally I would agree however WP NOR You need to have a precise source for the data estimations from data on other regions populations is considered original research No no and no If there are no GDP figures for any metropolitan area one can not cross calculate numbers on his own to make the term fit and still call it fact especially through calculations based on data so non sequitur as land area and population GDP is calculated on the number of businesses and the revenues thereof within a given territory not land and population If one insists on using the aire urbaine as a base for GDP he will have to do the data gathering in the said area himself as no fiscal data has ever been taken only in the wedge of extra IDF territory covered by the AU This sort of maniplation is the very example of Original Research Because it is in error is Original Research and unverifiable it is of no factual nor informative use to anyone Certainly not to Wiki