According to Dutch Law ( art 337 WvSr) the possession of counterfit goods in a amount of 3 or less is not punishable by law. Returning home from a holiday bringing 3 watches is not punishable, 4 or more watches you will have the choice to be prosecuted or to have the watches destroyed by customs.
Buying on internet is allways punsinable, if only 1 watch or 100, no difference. Customs will, if they seize your order, contact the brands and ask if it is gen or fake and will give the brandslaywers acces to your address.
All counties in Europe CAN follow the European guidelines concerning Piracy(art 11) but don't have to. Italy is starting a war against piracy and counterfeit goods this year. Fines up to 10.000 euro's and jailtime is a possibility.
Same in Belgium even possessing a replica is punsihable, you will be prosecuted or facing high fines up to 100.000 euro.
Seems like the Netherlands are behaving the same as with softdrugs, buying for own use is ok, selling in large quantities not