You Do Need power plug adapter while traveling from Guadeloupe 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 Guadeloupe are C and E. This is how they look like.

Guadeloupe

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

Type C

Type E

French Guiana

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

Type C

Type D

Type E