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

Denmark

In Denmark, outlets of type C, E, F and K are in use.

Type C

Type E

Type F

Type K

French Guiana

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

Type C

Type D

Type E