You Do Need power plug adapter while traveling from Pakistan to Benin.

Here is Why You Need An Adapter

The outlet and plug type used in Benin are C and E and in Pakistan are C and D. This is how they look like.

Pakistan

In Pakistan, outlets of type C and D are in use.

Type C

Type D

Benin

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

Type C

Type E