A new survey on the price of real estate globally suggests that Paris real estate is not the most expensive in the world even though many people believe real estate in Paris is the most expensive in the world.
According to this article in Explorimmo the top 4 most expensive cities in the world to invest in at this time are:
Hong Kong 13 356 Euros per m2
London 9663 euros per m2
New York 7941 per m2
Paris 7718 per m2
See the top ten by visiting the article in French here