Nothing epitomizes regulatory failure like the huge poster of Shein Ltd. Chairman Donald Tang at the BHV department store in Paris, where the Chinese e-commerce platform’s first physical outlet opened this week. For years now, consumer watchdogs in Europe have been warning about cheap and unsafe knock-offs arriving by the planeload from Shein and PDD Holdings Inc.’s Temu. Governments have done very little in response, even as a test this week found that 70% of orders from the two platforms inclu