“Ascenseur cassé” reads a sign next to the broken lift. Most walls are covered in protective foam and plywood; others have cables spilling from holes in the plasterboard. Revolut’s new EU headquarters in central Paris is ambitious and a work in progress, much like the bank itself.It is a fair bet that Nik Storonsky, the intense Russian-born entrepreneur who cofounded Revolut,12 years ago and remains its hard-charging chief executive, likes the theatrics of holding court in such a setting.Revolut has to some degree transformed Irish banking, adding more than 3 million customers and becoming the main day to day tool…