  The vast majority of extragalactic sources detected in the very high energy
(E> 100 GeV) domaine are active galactic nuclei (AGN) located at cosmological
distances. During their travel towards Earth, the emitted gamma-rays suffer
from absorption by the extragalactic background light (EBL). The density of the
EBL is not very well constrained by direct or indirect measurement which leads
to uncertainties on the intrinsic spectrum of the sources. High-quality AGN
spectra obtained with the High Energy Stereoscopic System (H.E.S.S.) have been
used to perform a model-independent measurement of the EBL spectral energy
distribution. While the precision of this measurement remains limited, it
reflects the sensitivity of H.E.S.S. alone to the EBL and offers the
possibility to access the intrinsic spectra of AGNs in a consistent manner,
taking into account the derived uncertainties on the EBL spectral energy
distribution.
  In this contribution, we study the intrinsic spectra as measured by H.E.S.S.
and by the Fermi Large Area Telescope (LAT) of several blazars of the H.E.S.S.
sky. This provides the opportunity to have new insight into the emission
processes at play in the jets of AGN. The data presented consist of monitoring
data of quiescent state of blazars and also bright blazar flares, such as
PKS~2155-304, Mrk~421, recorded by H.E.S.S.
