We report on Terahertz detection by inverted band structure HgTe-based Field Effect Transistor. Photoconductivity measurements allow for the observation of cyclotron resonance and Shubnikov-de-Haas-like oscillations. However, an unexpected peak was observed at the critical magnetic field value for which zero mode Landau Levels are crossing. Therefore, this specific feature of TeraHertz photoconductivity spectra can tentatively attributed to this magnetic field driven topological phase transition.