  Fundamental properties of the extinction curve, like the slope in the
rest-frame UV and the presence/absence of a broad absorption excess centred at
2175A (the UV bump), are investigated for a sample of 108 massive, star-forming
galaxies at 1<z<2.5, selected from the FDF Spectroscopic Survey, the K20
survey, and the GDDS. These characteristics are constrained from a parametric
description of the UV spectral energy distribution of a galaxy. It turns out
that the sample galaxies host dust producing extinction curves with properties
in between those of the Small and Large Magellanic Clouds (SMC and LMC,
respectively). LMC-like extinction curves, which exhibit a UV bump, are mainly
found among highly-reddened, UV-ultraluminous galaxies at z~2.4 and
highly-reddened, near-IR-bright, star-forming galaxies at z~1.2. We discuss
star-formation rates, total stellar masses, the morphology, and the chemical
properties of our sample galaxies with respect to possible explanations for the
different extinction curves.
