ΔE 7.9, close: similar, with a visible difference side by side. German Red Brown is a little darker, cooler than Leather.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). German Red Brown is a little darker, cooler than Leather.
The same difference applies the other way round: Leather is a little lighter, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Leather on the colour wheel See German Red Brown on the colour wheel
All matches: Leather equivalents · German Red Brown equivalents