the position of the peak of the thermal emission of dust in main-sequence galaxies from $\sim$80$\mu$m at z$\sim$0.4 to $\sim$30$\mu$m at z$\sim$3.75 in $\nu$L$_\nu$ units. The SEDs of strong starbursts have a much more modest evolution (from 50$\mu$m at to 30$\mu$m). The mean luminosity of the galaxies also increases very rapidly with redshift for both main-sequence and strong starburst galaxies.\
At z$>$2, we find that the peak of the dust emission tends to be broader than at lower redshift. The broadening of the mean SEDs induced by the size of the redshift bins has a major impact only on the mid-infrared, where the polycyclic aromatic hydrocarbon (PAH) features are washed out (see black and blue lines in Fig.\[fig:sedms\] and \[fig:sedsb\]), and cannot fully explain why the far-IR peak is broader at higher redshifts. The @Draine2007 model reproduces this broadening by means of a higher $\gamma$ coefficient, i.e., a stronger contribution of regions with a strong heating of the dust. This is consistent with the presence of giant star-forming clumps in high-redshift galaxies [e.g., @Bournaud2007; @Genzel2006]. The best-fit models at high z presents two breaks around 30$\mu$m and 150$\mu$m, which could be artefacts caused by the sharp cuts of the U 