In 1962-1963 four language areas were formally determined: the Dutch-language area (now also corresponding with the Flemish Region), the bilingual area of Brussels-Capital, (whose borders came to determine those of the present Brussels-Capital Region), the French-language area and the German-language area (together coinciding with Wallonia).
During the 1970s, many municipalities were merged into a bigger municipality in order to lessen administrative overhead.