An “ultra-prime” property on France’s sun-drenched Côte d’Azur clocked up the highest price per square foot for a property in 2014, at US$22,577. More properties above a value of $100million were listed in 2014 than ever before, according to a new study released by Christie’s International Real Estate.

“In 2014 we saw a real growth in resort and weekend markets around the world,” said Michael Sherman, vice president of corporate communications at Christie’s, New York. “This segment really exploded.

Christie’s believes that US$100million is now the “benchmark” for ultra-exclusive prime properties as more exceptionally wealthy consumers collect “trophy” properties. As the number of wealthy individuals rises, inventory in coveted markets is dwindling, says the third edition of the company’s Luxury Defined report.

Overall, homes priced at US$1million or more rose 16 percent in the 80 markets studied.