The business has been told to destroy all the data it had accumulated on people who did not use Facebook. The judiciary ruled the data was harvested illegally.
Belgium’s privacy watchdog said the website had breached privacy laws by placing tracking code known as cookies on third-party websites.
Facebook said it would petition against the ruling.
The social network faces damages of 250,000 euros £221,000, $311,000 a day if it does not comply.
The staff said Facebook must “stop tracking and reading internet use by people surfing in Belgium until it complies with Belgian privacy laws”.
“Facebook must also destroy all private data obtained illegally.”
The ruling is the freshest in a long-running dispute within the social network and the Belgian constitution for the protection of privacy (CPP).
In 2015, the CPP complained that Facebook tracked people when they attended pages on the site or clicked “like” or “share”, even if they were not members.
It won its case, but Facebook had the decision overturned in 2016.
Now the court has again agreed with the conclusions of the CPP.
Facebook said it was “disappointed” by the verdict.
Richard Allan, the company’s vice-president of government policy in Europe, said: “The cookies and pixels we use are industry standard technologies, and enable numbers of thousands of businesses to grow their businesses
Take your time to comment on this article.