You Do Need power plug adapter while traveling from Monaco to Dominican Republic.

Here is Why You Need An Adapter

The outlet and plug type used in Dominican Republic are A, B and C and in Monaco are C, E and F. This is how they look like.

Monaco

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

Type C

Type E

Type F

Dominican Republic

In Dominican Republic, outlets of type A, B and C are in use.

Type A

Type B

Type C