Belgian media reported that the detained suspect was not however fugitive Salah Abdeslam, who is one of Europe's most wanted men over his alleged involvement in the November 13 attacks that left 130 dead in the French capital.
"A search is ongoing in Brussels, one person was taken in for questioning," federal prosecutor spokesman Eric Van Der Sypt told AFP, confirming a report by Belgium's RTBF broadcaster.
Special forces from the federal police have been sent to the scene, he added, declining to give further details about the suspect.
Belgian police are still actively looking for 26-year-old, Brussels-born Abdeslam, suspected of having played a key role in the Paris attacks and understood to have returned to the Belgian capital the day after the bloodshed.
A source close to the Belgian investigation told AFP earlier today that Abdeslam made it past three police checks when friends drove him from Paris to Brussels in the hours after the coordinated gun and suicide attacks.