EU privacy law requires that prior consent must be given before issuing a cookie, a small file sent from a website to a user's browser, or applying similar technologies that access data stored on a user's device.
"Facebook tramples on European and Belgian privacy laws," Belgium's privacy protection commission said in a statement as quoted by the Guardian.
The statement added that Facebook "has shown itself particularly miserly in giving precise answers" to questions put to it by national regulators.
The watchdog recommended that Facebook refrained from collecting and using data through cookies and social plug-ins, while also calling on users to protect themselves from tracking by installing browser add-ons.
Facebook uses tracking to adjust its targeted advertising, a source of growing revenue for the US company.
Earlier this week, Facebook was ranked 17th in the list of the world's biggest technology companies, compiled annually by Forbes magazine.
