I do find it quite odd that the Belgian flag has the same colours as the German one rather than the French/Dutch, given that the German-speaking community there is tiny compared to Flanders & Wallonia.

Although having just nerd-sniped myself with that, it turns out that they are not the German colours, they are the Duchy of Brabant colours, and the yellow on the Belgian flag is in fact slightly paler than the gold on the German flag. And apparently the flag of Flanders is a black lion with a red tongue on a yellow background, and Wallonia is a red cock on a yellow background.