Parliament is moving to tax the small parcels arriving from Chinese platforms such as Shein and Temu.
The National Council on Monday backed a motion by 130 votes to 63 to introduce the tax, after the Council of States had already approved it.
A second motion, passed 140 to 47, will require these platforms to clearly label any products that do not meet Swiss legal standards.
Supporters say the move will help fund stronger checks on the millions of small packages crossing into Switzerland each year.
A minority of the SVP and the Federal Council had opposed both proposals.
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