  We use the most homogeneous $Geneva$ seven-colour photometric system to
derive new metallicity calibrations for early A- to K-type stars that cover
both, dwarf stars and giants. The calibrations are based on several
spectroscopic data sets that were merged to a common scale, and we applied them
to open cluster data to obtain an additional proof of the metallicity scale and
accuracy. In total, metallicities of 54 open clusters are presented. The
accuracy of the calibrations for single stars is in general below 0.1 dex, but
for the open cluster sample with mean values based on several stars we find a
much better precision, a scatter as low as about 0.03 dex. Furthermore, we
combine the new results with another comprehensive photometric data set to
present a catalogue of mean metallicities for more than 3000 F and G-type dwarf
stars with $\sigma \sim 0.06$ dex. The list was extended by more than 1200
hotter stars up to about 8500 K (or spectral type A3) by taking advantage of
their almost reddening free characteristic in the new $Geneva$ metallicity
calibrations. These two large samples are well suited as primary or secondary
calibrators of other data, and we already identified about 20 spectroscopic
data sets that show offsets up to about 0.4 dex.
