ΔE 9.6, close: similar, with a visible difference side by side. French Blue is more muted, cooler than Gothic Blue.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). French Blue is more muted, cooler than Gothic Blue.
The same difference applies the other way round: Gothic Blue is more saturated, 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 Gothic Blue on the colour wheel See French Blue on the colour wheel
All matches: Gothic Blue equivalents · French Blue equivalents