I feel that if that law was to pass, the affected companies would simply add that 3% tax to the prices European consumers pay, especially since this is a tax on the revenue and not on profit.
It's not like US tech giants have much competition to fear from European companies anyway. A 3% price increase isn't going to get anyone to switch to another service (except maybe in the case of Amazon's physical sales).
In the end, consumers would pay and this would add to the already large price difference between the EU and the US, due to the much higher applicable VAT in the EU, as well as other similar taxes applied in some EU countries (private copying levy [0], eco-participation [1]...).
It's not like US tech giants have much competition to fear from European companies anyway. A 3% price increase isn't going to get anyone to switch to another service (except maybe in the case of Amazon's physical sales).
In the end, consumers would pay and this would add to the already large price difference between the EU and the US, due to the much higher applicable VAT in the EU, as well as other similar taxes applied in some EU countries (private copying levy [0], eco-participation [1]...).
[0] https://en.wikipedia.org/wiki/Private_copying_levy
[1] https://fr.wikipedia.org/wiki/Éco-participation