  Dust attenuation shapes the spectral energy distributions of galaxies and any
modelling and fitting procedure of their spectral energy distributions must
account for this process. We present results of two recent works dedicated at
measuring the dust attenuation curves in star forming galaxies at redshift from
0.5 to 3, by fitting continuum (photometric) and line (spectroscopic)
measurements simultaneously with CIGALE using variable attenuation laws based
on flexible recipes. Both studies conclude to a large variety of effective
attenuation laws with an attenuation law flattening when the obscuration
increases. An extra attenuation is found for nebular lines. The comparison with
radiative transfer models implies a flattening of the attenuation law up to
near infrared wavelengths, which is well reproduced with a power-laws recipe
inspired by the Charlot and Fall recipe. Here we propose a global modification
of the Calzetti attenuation law to better reproduce the results of radiative
transfer models.
