You Do Need power plug adapter while traveling from San Marino to Niger.

Here is Why You Need An Adapter

The outlet and plug type used in Niger are C, D, E and F and in San Marino are C, F and L. This is how they look like.

San Marino

In San Marino, outlets of type C, F and L are in use.

Type C

Type F

Type L

Niger

In Niger, outlets of type C, D, E and F are in use.

Type C

Type D

Type E

Type F