You Do Need power plug adapter while traveling from French Guiana to Sint Maarten.

Here is Why You Need An Adapter

The outlet and plug type used in Sint Maarten 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

Sint Maarten

In Sint Maarten, outlets of type A and B are in use.

Type A

Type B