ΔE 18.4, loose: different enough that you should pick on purpose. French Blue is much more muted, cooler than Navy Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). French Blue is much more muted, cooler than Navy Blue.
The same difference applies the other way round: Navy Blue is much 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 Navy Blue on the colour wheel See French Blue on the colour wheel
All matches: Navy Blue equivalents · French Blue equivalents