I had never heard of Renault Duster before (nor seen one), so I looked it up. The Renault Duster is apparently a Dacia Duster with mostly cosmetic changes, for sale outside the eu, typically released later than the Dacia Duster is released in the eu. So it's the same car, but different brand badges + cosmetics depending on the country were it's sold. They are so similar, that I'd just call it the same car, not a copy.