The underlying mechanism driving the structural amorphous-to-crystalline transition in Group VI chalcogenides is still a matter of debate even in the simplest GeTe system. We exploit the extreme sensitivity of 57 Fe emission Mössbauer spectroscopy, following dilute implantation of 57 Mn (T½= 1.5 min) at ISOLDE/CERN, to study the electronic charge distribution in the immediate vicinity of the 57 Fe probe substituting Ge (Fe Ge), and to interrogate the local environment of Fe Ge over the amorphous-crystalline phase transition in GeTe thin films. Our results show that the local structure of as-sputtered amorphous GeTe is a combination of tetrahedral and defect-octahedral sites. The main effect of the crystallization is the conversion from tetrahedral to defect-free octahedral sites. We discover that only the tetrahedral fraction in amorphous GeTe participates to the change of the Fe Ge-Te chemical bonds, with a net …