Question

how Belgium has become successful model

Answer 1

Becoz they accomodatwd constitution acceptable by all

Answer 2

Belgium became an successful model to all over the world as they accommodated their ethnic composition peacefully. They went on the process as follows:
(i) Ethnic composition: 
In Brussels - French (80%)  and   Dutch (20%)
All over the nation - Dutch (59%) , French (40%) and German (1%)
(ii) As the minority French being more powerful, there exist a tension on benefit of economic developmental process during 1950s and 1960s.
(iii) The Belgian leaders took a different path in solving these tensions. Between 1970s and 1993, the constitution was amended four times.
(iv) It says that the no of Dutch and French ministers should be equal in no.
(v) Powers to be shared between states and central with no dominance over other.
(vi) Separate govt for Brussels and The Rest of the country as the majority composition is vice-verse in the capital and country.
(vii) Third kind of govt "Community govt", that people elect one language community (Dutch, French, German).
Thus by this Belgian model worked well so far which avoided the civic strife between the two major communities.

By this Belgium become a successful model for the world in means of
running their gov't by power sharing.


^_^ Hope this Helps !!!