You Do Need power plug adapter while traveling from Balearic Islands 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 Balearic Islands are C and F. This is how they look like.

Balearic Islands

In Balearic Islands, outlets of type C and F are in use.

Type C

Type F

French Guiana

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

Type C

Type D

Type E