Fir tree or spruce?

The High-Jura is well-known for its softwood forests, comprised of fir trees and spruces, two species with shared characteristics (conical shape; and with persistent needles). How to differentiate between them?
On the fir tree, cones are directed upwards, its flat needles have two white lines on the underneath and their position on either side of the sprig is reminiscent of a comb; whilst on the spruce, cones fall downwards, the needles are sharp and positioned like a brush, all around the sprig.