As a rule the GHS-labelling system has to be implemented in every country separately. But for all countries which are members of the EU it is the EU-government which has implemented the GHS by the CLP-regulation ("Classification, labelling and packaging"). This regulation has a direct legal effect for all EU-countries. This means that all things concerning classification, labelling and packaging are regulated in all these countries in the same way.
As a rule it is the job of the manufacturers to classify their offered chemicals. A special feature of the clp-regulation is that in annex VI there are approximately 3000 compounds listed with their classification. This means that for these compounds the labelling is fixed and must be applicated in all EU-countries in the same way. This is called a "harmonised classification".