"The fastest rate of increase was in Boston," Douglas Poutasse, investment strategy chief for AEW, tells GlobeSt.com. "Boston even passed Paris this year."

The survey included 70 different metropolitan areas worldwide. The only markets more expensive than Boston were London, Tokyo, Hong Kong and New York. "Boston went from being a moderately expensive city to being an extraordinarily expensive city," notes Poutasse. In a two-year period, rents in the city's towers went from the low $40s per sf to $80 per sf.

The high costs, adds Poutasse, have the effect of driving people out of Downtown. "People are pushed to seek alternatives," he says. "It will eventually drive them out of the Boston area." The recent slowdown in the economy is barely being felt here. "People aren't signing those $80 leases now, but there is no space available in the best buildings," Poutasse points out.