This study reports the effect of fluorination on germanene-graphene hybrid within DFT. Stability, structural, electronic and magnetic properties of full-fluorinated F-GeC-F and two semi-fluorinated F-GeC and GeC-F configurations are discussed. Calculations reveal that fluorination is an exothermic adsorption leading to stable structures. Moreover, it is shown that controlling the adsorbed atoms modulates the properties. It is found that chemical modification with F-atoms increase the gap and induce magnetism in F-GeC, however it reduces the gap in non-magnetic F-GeC-F and in ferromagnetic GeC-F. The findings of this work open a spectrum of possible new GeC-based nanodevices with controlled and tuned properties. (C) 2016 Elsevier B.V. All rights reserved.