  In this work we present a comprehensive investigation on magnetic and
thermodynamic properties of the two-dimensional layered honeycomb system
Cr$_2$Ge$_2$Te$_6$. Using magnetization and specific heat measurements under
magnetic field applied along two crystallographic directions we obtain the
magnetic phase diagram for both directions. Cr$_2$Ge$_2$Te$_6$ is a ferromagnet
with a Curie temperature $T_C=65$ K and exhibits an easy magnetization axis
perpendicular to the structural layers in the $ab$-plane. Under magnetic fields
applied parallel to the hard plane $ab$ below the magnetic saturation, a
downturn with an onset temperature $T\textrm{*}$ is observed in the temperature
dependent magnetization curve. $T\textrm{*}$ shows a monotonous shift towards
lower temperatures with increasing field. The nature of this anisotropic and
specific behavior for fields in the hard plane is discussed as an interplay
among field, temperature and effective magnetic anisotropy. Similarities to
structurally related compounds such as CrX$_3$ (X = Br, I) hint towards a
universality of this behavior in ferromagnetic quasi two-dimensional honeycomb
materials.
