The new €3 customs duty on low-value imports from outside the EU, which came into effect on Wednesday, is a modest but defensible intervention. It is designed to level a playing field that had tilted dramatically against European retailers.Until this week, a platform such as Shein or Temu could ship a blouse to a consumer in Dublin or Dortmund without paying a cent in customs duty, while the domestic retailer selling the same item bore all the costs of operating inside the Single Market. The underlying logic of the change is hard to argue with. VAT was already supposed to apply to these purchases, but the customs duty exemption for anything valued under €150 gave offshore sellers a structural advantage due less to price competition than to regulatory arbitrage.The frictionless global trading environment that the internet once seemed to promise has been in retreat for some years now. US tariff policy, Brexit, the unravelling of the WTO’s authority, and now this modest EU measure all represent friction being quietly reintroduced into systems that once appeared seamless. The old consensus has frayed. The €3 charge will add cost and complexity for consumers, particularly on smaller purchases, and there will be understandable frustration among shoppers who order from British retailers and find their parcels subject to the same rules as a Shein haul.Still, the case for some intervention in the fast fashion end of this market is not just economic. The volume of cheap, disposable clothing shipped directly from Chinese factories to individual consumers is among the more visible expressions of an unsustainable consumption model. Clothes manufactured to be worn once or twice, then discarded, represent an environmental cost that has been socialised while the profits are privatised. A €3 duty will not transform that reality on its own. But at least it reminds us of a fact that three decades of frictionless global trade had encouraged us to forget. Cheap does not mean costless, and borderless does not mean consequence-free.