Comparison of the photometric metallicities in the Pristine-Gaia synthetic and the Pristine DR1 catalogues for a random 10% of the overlap between the two catalogues. Points are colored by the uncertainties on the photometric metallicities from the Pristine-Gaia synthetic catalogue and small and large dots correspond to stars with a loose and tight quality cut on the metallicity uncertainties, respectively (δ[Fe/H]_phot < 0.5 and 0.3). The dashed lines correspond to the one-to-one lines and the dotted lines show offsets of 0.2 dex from them. As expected, the metallicities derived from the two sets of magnitudes are consistent since they are on the same photometric system. The next three panels show the impact of quality cuts to clean the sample by removing stars with a probability of being variable (P_var > 0.3; second panel), flagged as potentially problematic in Gaia (RUWE> 1.4 and |C* | > σ_C* ; third panel), or at the edge of the grid (fourth panel; here we shown all the catalogue stars that follow this criterion). The different quality cuts remove stars that do not behave as expected.