Five colour–colour diagrams for stars in the le Phare library (black filled circles) and the 15 to 23 objects detected at all GROND bands, with the most accurate photometry in the relevant bands and robustly classified as stars by le Phare using the full seven-channel photometry (red asterisks). These observed stars nicely fall onto the synthetic stellar sequences, after the synthetic photometry is slighlty corrected by  −0.05, +0.025 and  +0.025   mag in the r′,i′ and H bands, respectively. We recall that photometric redshifts are particularly sensitive to the 4000   Å break in the spectrum of a galaxy, which spans the entire wavelength range of the z′ broad-band filter for z = 1.1−1.6.