Stellar mass–stellar metallicity relation of star-forming galaxies at z ∼ 3 in GAEA, for the whole population (panel 1), centrals (panel 2), and satellites (panel 3), in different bins of virial mass of their host FoF groups from 10¹¹ to 10¹³ M_⊙. The vertical error bars represent the median absolute deviation of the galaxy metallicities in each stellar mass bin. Panels 4–6: same as panels 1–3, but for the cold gas metallicity.