You Do Need power plug adapter while traveling from United States of America (US) USA 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 United States of America (US) USA are A and B. This is how they look like.

United States of America (US) USA

In United States of America (US) USA, outlets of type A and B are in use.

Type A

Type B

French Guiana

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

Type C

Type D

Type E