There is an official Flemish (Dutch), French and Germam version. The earliest version was French. It's still has the French title "La Brabançonne".Is it Flemish or French?
Most Belgians don't know the lyrics (me neither). The first champion I saw singing it without hesitation was ... you probably can guess it ... Evenepoel. It's funny if you see the Belgian Red Devils singing it. They just mumble something.