You Do Need power plug adapter while traveling from Saudi Arabia 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 Saudi Arabia is G. This is how they look like.

Saudi Arabia

In Saudi Arabia, outlets of type G are in use.

Type G

French Guiana

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

Type C

Type D

Type E