Not sure if you are referencing something else but in the case of VAT (sales tax) this is simply not true, see: VAT one stop shop / moss. There are also no cust

Not sure if you are referencing something else but in the case of VAT (sales tax) this is simply not true, see: VAT one stop shop / moss. There are also no customs duties on inter-state shipments. Employment regulations are different - if you have a lot of people working for you in another member state you'll need a branch office or subsidiary there (or you can easily outsource it via services like https://www.playroll.com/ https://www.playroll.com/)