The case starts in Italy (=state law) and is passed up to the European court in Brussels (=federal law). Do not let a Europhile read those terms but that is what it is equivalent to. It does not matter what is decided at local level, if Brussels decides otherwise the local law is trumped.
It is not passed up to an "European court". It is a Belgian court seated in Brussels which will have to rule according to Belgian law. Both The Italian and Belgian courts have some common ground, because the national laws are based on EU directives. EU directives are legal frameworks, but leave it up to national laws to decide on fines, for example.
The European court of justice is seated in Luxembourg, and has no business in the present case.