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

Here is Why You Need An Adapter

The outlet and plug type used in Rwanda are C, E, F and G 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

Rwanda

In Rwanda, outlets of type C, E, F and G are in use.

Type C

Type E

Type F

Type G