ΔE 19.3, loose: different enough that you should pick on purpose. Golden Griffon is a little darker, much more saturated, warmer than Medium German Yellow.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Golden Griffon is a little darker, much more saturated, warmer than Medium German Yellow.
The same difference applies the other way round: Medium German Yellow is a little lighter, much more muted, cooler.
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 Medium German Yellow on the colour wheel See Golden Griffon on the colour wheel
All matches: Medium German Yellow equivalents · Golden Griffon equivalents