  In this work we present a systematic Raman Scattering study in the
Ca$_{1-x}$% Eu$_{x}$B$_{6}$ series ($0.00\leqslant x\leqslant 1.00$). Our
results are the first experimental evidence for the occurrence of a local
symmetry break of the crystalline structure in this system. The local symmetry
of some Boron octahedra is tetragonal instead of cubic. This result may explain
the appearance of ferromagnetism in Eu-hexaborades since magnetic ordering is
forbidden in the $O_{h}$ space group of this system.
