As fast-fashion giant Shein prepares for its long-awaited Hong Kong stock market debut, the business model behind its rise is coming under pressure. Europe has become a key regulatory battleground, with tougher rules, fines and investigations. On Sep 1, France will begin imposing financial penalties on ultra-fast fashion products. In Italy, the Competition Authority fined Shein US$1.2 million last year over what it said were misleading and deceptive environmental messages and claims. EU regulators are looking into Shein over alleged fake discounts and pressure-selling tactics. Ross Cullen reports from Paris.