You Do Need power plug adapter while traveling from Chile 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 Chile are C and L. This is how they look like.

Chile

In Chile, outlets of type C and L are in use.

Type C

Type L

French Guiana

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

Type C

Type D

Type E