The European Union is an organisation which requires its member states:
Not to carry out any customs checks on any goods travelling directly from one member state to another member state
To carry out customs checks on any goods coming into the member state from a "third state" (i.e. from a country which is not a member of the EU).
The checks which a member state is required to carry out under (2) above are (a) checks for conformity of goods to EU regulations (b) collection of tariffs which the EU imposes on the import of third state goods.
Is there any historical precedent where a member state have been, in the opinion of the EU Commission, insufficiently thorough in carrying out the checks in 3 above (perhaps because of a land border which is difficult to police, or because of a cultural sensitivity such as where the third state, of part of it, has historically been part of the member state and is viewed as part of a cultural continuum, or for any other reason, practical or political/cultural) and the EU Commission has ordered the "quarantining" of the member state - i.e. imposing checks on goods travelling from that member state to other member states (i.e. checks which would not normally be allowed under 1 above)?