You Do Need power plug adapter while traveling from French Guiana to Trinidad & Tobago.

Here is Why You Need An Adapter

The outlet and plug type used in Trinidad & Tobago are A and B and in French Guiana are C, D and E. This is how they look like.

French Guiana

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

Type C

Type D

Type E

Trinidad & Tobago

In Trinidad & Tobago, outlets of type A and B are in use.

Type A

Type B