Left panel: comparison of the [M/H] metal abundances (mh_gspspec) computed with the GSP_Spec module of Apsis and [Fe/H] metallicities computed with the SOS Cep& RRL pipeline for 193 RR Lyrae stars for which both values are available. The two dashed lines are offset by ±0.46 dex, the mean error of the photometric metallicities (see Fig. 19), from the one-to-one line; right panel: same as in the left panel, but also showing the error bars of the [M/H]GSP_Spec and [Fe/H]_SOS metallicities.