Grown mainly in central France, French Oak is delicate and must be hand-split into staves to produce barrels. As a result, French barrels are higher priced than American Oak barrels which can be cut much faster with saws.
Aging in French oak will give whisky subtle pepper spiciness and notes of vanilla compared to aging in American Oak. French Oak barrels are often used by American rye producers to heighten the spicy, peppery notes of their whiskey.