The variation by state is weird - was in Washington DC and the rate was X on clothing, drove 2 spits into Virginia to a massive shopping mall (Tysons Corner) and tax was about 25% lower - ditto variables in the New England states. But then in the corners between France/Switzerland and France/Germany there is a massive influx of Swiss & Germans to French hypermarkets as prices and taxes are lower.
It's a fair comparison, the level of Federating up to the Federation in the US is reasonably low, in some areas the theoretically Confederal EU has been granted more powers by its members than the US states have their federal government.
The major shopping market (
https://goo.gl/maps/dnDwnMG5wHu8dNH17) for Basel however is in Germany not France, due to the differing political situation in relation to customs between France&Germany and Switzerland, there's a dedicated exit for Switzerland that leads consumers directly into Swiss customs car boot checks, and they check every boot.
The plaza was being rebuild when I was there, but you can get a decent look at it with a bit of clicking in streetview (Where many angles are also of it being rebuilt), the set up is such that vehicles entering Germany are slowed down, but those entering Switzerland have to stop.
They had no interest in pedestrians, so I guess if you want to smuggle toothpaste into Switzerland, then loading the lining of your jacket up spiv like is the way to do it.