Carmenère is a well-travelled French variety that found its second home in Chile where it is now so widely grown that Chile is the world’s top producer of the variety, making 98% of it!
While it adapted to Chile very well, it was under the guise of a different variety – Merlot – that Chilean wine producers planted and produced it. The slightly different style that this Merlot in Chile produced from the Merlot found in other parts of the world led Chilean winemakers and drinkers to call it ‘Merlot Chileno’ as opposed to just plain old Merlot. This was indeed very different from any other Merlot because, as the intrepid French ampelographer Jean Michel Boursiquot discovered in 1994, it was, in fact, the long-lost French variety, Carmenère. He spotted the error because Carmenère has distinctive twisted stamens (unlike Merlot and most other grape varieties).
Since 1994, not only the name of the variety changed but viticulturists and winemakers began working the variety in a different way and the style changed. The separation of varieties also changed the style of Chilean Merlot, although if you find a pre-1994 bottle of Merlot, it could likely be Carmenère.