You Do Need power plug adapter while traveling from Yemen 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 Yemen are A, D and G. This is how they look like.

Yemen

In Yemen, outlets of type A, D and G are in use.

Type A

Type D

Type G

French Guiana

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

Type C

Type D

Type E