Cabernet Franc is grown throughout the world, but particularly in Bordeaux.  It fares best as Bouchet in St-Emilion and at Pomerol, across the Dordogne River, where Cabernet Sauvignon is less well represented.  Grown under neutral conditions, it might not be easy to distinguish any significant varietal differences between the two Cabernets, but, suited as they are to different situations, the Cabernet Franc tends to produce a slightly earthy style of wine that is very aromatic, but has less fine characteristics on the palate when compared to the Cabernet Sauvignon.

Info : The Sotheby's Wine Encyclopedia 4th Ed by Tom Stevenson