You Do Need power plug adapter while traveling from Senegal to French Guiana.

Here is Why You Need An Adapter

The outlet and plug type used in French Guiana are C, D and E and in Senegal are C, D, E and K. This is how they look like.

Senegal

In Senegal, outlets of type C, D, E and K are in use.

Type C

Type D

Type E

Type K

French Guiana

In French Guiana, outlets of type C, D and E are in use.

Type C

Type D

Type E