Reverse charge mechanism: how to apply it?

The generalized reverse charge mechanism has been introduced in Belgium since 2002 and is applicable to all supplies of goods and services that are deemed to take place in Belgium and performed by a taxable person not established in Belgium (i.e. established in another EU Member state or outside the EU) to a customer:

Established in Belgium and filing periodical Belgian VAT returns or;
Not established in Belgium but being VAT registered in Belgium and having appointed a fiscal representative.

Source: vatdesk.eu