https://www.techdirt.com/articles/20211003/17223447690/belgian-government-wants-to-add-encryption-backdoors-to-already-terrible-data-retention-law.shtml

Earlier this year, a data retention law passed by the Belgian government was overturned by the country's Constitutional Court. The law mandated retention of metadata on all calls and texts by residents for one year, just in case the government ever decided it wanted access to it. Acting on guidance from the EU Court on laws mandating indiscriminate data retention elsewhere in the Union, the Constitutional Court struck the law down, finding it was neither justified nor legal under CJEU precedent or under Belgium's own Constitution.

[T]he Constitutional Court finds that the Data Retention Act aims at broader objectives than safeguarding national security, combating serious crime and preventing serious threats to public security and that the interference is thus not limited to what is strictly necessary. In addition, the Constitutional Court points out that such requirement to retain traffic and location data should be the exception, not the rule, must set out clear and precise rules regarding the scope and application of such measure, whereby certain minimum requirements should be implemented, and should ensure that the interference is limited to what is strictly necessary.