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

Here is Why You Need An Adapter

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

Poland

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

Type C

Type E

Mauritius

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

Type C

Type G