In the Netherlands the dividend tax is 0% for dutch citizens.
If you were taxed 30% in the US then:
1- the W8BEN reduces that to 15%
2- you get the 15% back from the dutch tax authorities. 15% is also the max % you can get back.
A few years ago I had LYB which has a NL isin and no tax was deducted from the LYB dividend.
BASF for example has a DE isin and has a german dividend tax around 20%. From the dutch tax office you get 15% back and everything over 15% you have to get back from Germany yourself.
Not all German companies have a dividend tax over 15%, DT last time they paid dividend had a zero tax %.
I am not aware of general rules for the company div tax percentage. French companies also have div tax over 15%, which you need to reclaw yourself, which is a hassle.