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

Here is Why You Need An Adapter

The outlet and plug type used in Chad are C, D, E and F 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

Chad

In Chad, outlets of type C, D, E and F are in use.

Type C

Type D

Type E

Type F