Question about Tamron AF 70-180mm f/2.8 Di III VXD

Can you please explain that in Europe this lens costs as little as 1350 euros (1420 chf) including 20% tax but here with only 7.7.% tax you want 1699 chf which is considerably higher than the lenses recommended retail price. I could fly to America and buy it there at the retail price of 1199usd with the same amount of money that it costs here.