The planners behind last month's bombings in Brussels which killed 32 people had initially planned to attack Paris but struck closer to home as investigators made arrests among key suspects.
Belgian prosecutors say their investigation has shown that the terrorist group initially had the intention to strike in France again.
But they say the group was surprised by the speed of progress in the investigation and took the decision to strike in Brussels.
Investigations into the 13 November Paris attacks which killed 130 people showed many of the attackers lived in Belgium, including key suspects Salah Abdeslam and Mohamed Abrini who evaded police for four months after November's killings.
Abrini was arrested on Friday and admitted to having participated in the Brussels airport bombings. He has been charged with terrorist murders, prosecutors said.