You Do Need power plug adapter while traveling from Mauritius to Belgium.

Here is Why You Need An Adapter

The outlet and plug type used in Belgium are C and E and in Mauritius are C and G. This is how they look like.

Mauritius

In Mauritius, outlets of type C and G are in use.

Type C

Type G

Belgium

In Belgium, outlets of type C and E are in use.

Type C

Type E