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

Here is Why You Need An Adapter

The outlet and plug type used in Peru are A, B and C and in Benin are C and E. This is how they look like.

Benin

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

Type C

Type E

Peru

In Peru, outlets of type A, B and C are in use.

Type A

Type B

Type C