Belgium – Religion
The majority of Belgians are Roman Catholic, but regular attendance at religious services is variable. Although it is marked in the Flemish region and the Ardennes, regular attendance at church has decreased in the Walloon industrial region and in Brussels, and nearly one-third of Belgians are nonreligious. The relatively few Protestants live mostly in urban areas in Hainaut, particularly in the industrial region known as the Borinage, and in and around Brussels. Several municipalities on the north and west sides of Brussels—notably Schaerbeek—are home to many Muslim immigrants. The country’s small Jewish population is concentrated in and around Brussels and Antwerp.

Belgium: Religious affiliation. Source: Encyclopædia Britannica, Inc.
https://www.britannica.com/place/Belgium/Ethnic-groups-and-languages