You Do Need power plug adapter while traveling from French Guiana to New Zealand.

Here is Why You Need An Adapter

The outlet and plug type used in New Zealand is I 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

New Zealand

In New Zealand, outlets of type I are in use.

Type I