This is understandable and will help integration. Belgium has 3 federal communities - Flanders (north, near the Netherlands, speaking Flemish), Wallonia (south, near France, speaking French), and Brussels (middle, supposedly bilingual, in effect 85% French speaking). Merchtem is in Flanders. The schooling is of course given in Flemish, and with a fair number of francophone Belgians settling in the area, he wants to preserve the Flemish culture of the schools and ensure that the francophone children integrate rather than forming a francophone sub-community within the schools.
This is petty and seeking votes. The Flemish currently resent Wallonia because Flanders is currently economically stronger, and resent the Walloons for settling in Flemish towns and francophonising them - the communes [think local council regions] in & around Brussels are the particular sore point. So a strong line for Flanders does well in elections. Next communal elections? October.
Two sides to any story eh?
Meanwhile, the British government is providing council literature (health care, schooling, etc.) in immigrant languages so that they don't have to learn English and integrate. In Belgium, English is frequently the solution - the neutral language everyone learns and speaks well so they can communicate between the official languages. In England, it seems English is the problem - the official language no-one learns and speaks well...
But perhaps it's the reverse culture shock speaking.