  We present the first search for bosonic super-WIMPs as keV-scale dark matter
candidates performed with the GERDA experiment. GERDA is a neutrinoless
double-beta decay experiment which operates high-purity germanium detectors
enriched in $^{76}$Ge in an ultra-low background environment at the Laboratori
Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for
pseudoscalar and vector particles in the mass region from 60 keV/c$^2$ to 1
MeV/c$^2$. No evidence for a dark matter signal was observed, and the most
stringent constraints on the couplings of super-WIMPs with masses above 120
keV/c$^2$ have been set. As an example, at a mass of 150 keV/c$^2$ the most
stringent direct limits on the dimensionless couplings of axion-like particles
and dark photons to electrons of $g_{ae} < 3 \cdot 10^{-12}$ and
${\alpha'}/{\alpha} < 6.5 \cdot 10^{-24}$ at 90% credible interval,
respectively, were obtained.
