ΔE 10.6, fair: the same colour family, but not a straight swap. Dark Red is a little lighter, more muted than RAL 8013 Rotbraun.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Dark Red is a little lighter, more muted than RAL 8013 Rotbraun.
The same difference applies the other way round: RAL 8013 Rotbraun is a little darker, more saturated.
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 RAL 8013 Rotbraun on the colour wheel See Dark Red on the colour wheel
All matches: RAL 8013 Rotbraun equivalents · Dark Red equivalents