Differences between input redshift of the model catalogues and output photometric redshift estimates. Top three panels: differences Δz normalised by (1 + z) as a function of input redshift for three investigated p_B5D extinction values: p_B5D = 0.02, 0.1 and 0.3 (pD values indicated in the upper right corner). The grey zone indicates the constrains on the photo-z bias required to achieve the precisions on the cosmological parameters set by the upcoming weak-lensing surveys such as Euclid i.e. ⟨ z ⟩ < 0.002(1 + z). Bottom panel: input versus output redshifts for p_B5D = 0.3. Vertical grey lines at z = 0.5, 1 and 1.5 are plotted to guide the eye. The impact of neglecting the Galactic absorption dependence with SED can directly be assessed from the divergences from the identity line.