L_[CII]–SFR relation. Predictions from our model are shown for a set of redshifts from z = 4 to z = 7.6. In each panel the whole sample of G.A.S. galaxies is shown in grey scale. The average relation is plotted with a solid black line. The black dashed line shows the relation given in Eq. (10). Yellow to red coloured points mark the gas metallicity of a randomly selected sample of simulated galaxies (note that the observed tendency of high-metallicity galaxies to fall either above or below the mean trend, that is to make an envelope, is only a trick of the eye caused by the plotting; galaxies with high metallicities (Z_g> 8.8) are spread over the whole area, with a higher density of objects at high SFR). Our predictions are compared to a large sample of observational data that are detailed in Table B.1. Amplification corrections on luminosity and SFR, when available, are applied. For dusty star forming galaxies, SFR are converted directly from L_IR using the Kennicutt (1998) conversion factor assuming a Chabrier (2003) IMF where SFR (M_⊙ yr^-1) = 1.0 × 10^-10L_IR(L_⊙). The blue solid line shows the De Looze et al. (2014) relation for the local dwarf galaxy sample.