Due to the increase in office space, Lex 2000 has had to finance renovation of nearby apartments to compensate.

At the time, the existing Justus Lipsius building could not be extended due to residential areas and the then-existing conservation orders on the adjacent Résidence Palace (later partially demolished and renovated to become the Europa building), thus Lex became a new project to satisfy the need for more office space.

The authorities demanded a reduction of 20 metres (66 ft), giving it 15 floors instead of the planned 20, in order to preserve the visual dominance of the Berlaymont building and the Cinquantenaire Arcade.

The main entrance has direct links to the metro and rail stations with the ground floor being occupied by a large restaurant.

The building's glass structure is intended to convey transparency, with two floors being cleared to give a more open feel inside.