Question

Can someone explain this in more detail?

When Belgium became independent from the Netherlands, they were mad at the Netherlands and the French took advantage of that by forcing their culture upon the Dutch speaking Flemish. That is the simple explanation.

Answer 1

The people of the south were mainly Flemings and Walloons. Both peoples were traditionally Roman Catholic as contrasted with Protestant-dominated (Dutch Reformed) people of the north. Many outspoken liberals regarded King William I's rule as despotic. There were high levels of unemployment and industrial unrest among the working classes.

On 25 August 1830, riots erupted in Brussels and shops were looted. Theatregoers who had just watched the nationalistic opera La muette de Portici joined the mob. Uprisings followed elsewhere in the country. Factories were occupied and machinery destroyed. Order was restored briefly after William committed troops to the Southern Provinces but rioting continued and leadership was taken up by radicals, who started talking of secession.