Transit Services - T1 and T2 documents
When EU-goods (produced or imported in the EU) are being shipped within the EU, for instance from Spain, through France to Belgium, no customs declaration has to be done.
However, when non-EU-goods are shipped inside the EU, a transit document, or T1-document is needed. This document has to accompany the goods during transport at all times. This T1-document inform that no taxes/duties have been paid yet.
When EU-goods (produced or definitely imported in the EU), are being shipped from one place inside the EU to another place inside the EU, but are crossing a third country such as Norway, Switzerland, …, a T2-document is needed. The T2-document will prove to the EU customs officer that the goods are from EU-origin and that no import duties have to be paid.