A Belgian national named only as Y.A. was charged on Saturday with participating in terrorist activities over a foiled plot to attack France.
"He has been charged with participation in the activities of a terrorist group," the federal prosecutor's office said in a statement, adding that the development was part of a joint investigation by France and Belgium.
The 33-year-old appeared before a judge on Friday, who had remanded him to custody. He was detained late on Thursday.
Two others - Abderrahmane A. and Rabah M. - are also being held in Belgium over the same plot.
Prosecutors said the charge related to the investigation into Reda Kriket, a Frenchman arrested in a Paris suburb on March 24, two days after the Brussels bombings, and suspected of planning an imminent act of "extreme violence."
Paris' Prosecutor Francois Molins said on Wednesday that Kriket, who was imprisoned for 10 years in absentia by a Belgian court last July, over recruiting DAESH terrorists for Syria, said in questioning by French investigators that he was not a terrorist, but gave up little information.
The Netherlands is also holding a French national, Anis Bahri, in connection with the same plot and he is currently fighting his extradition to France.