They say in Paris that all roads lead to Arnault. That's Bernard Arnault, whose ruthless approach to acquisitions has earned him the nickname "the wolf in cashmere" and helped him recently to overtake Warren Buffett as the world's third-richest man.

His empire permeates Paris. Just the other day his luxury group LVMH launched a new maison with pop star Rihanna; when a fire devastated Notre-Dame, the Arnault family was on hand with a €200 million ($345.7m) donation to fund its reconstruction.

But the man himself is deeply private. Our lunch is almost 18 months in the making. Not one to