Abstract : The structure of nuclei far from stability call be investigated by means of in-beam gamma spectroscopy using both stable and radioactive beams. A gamma -array consisting of BaF2 and Ge detectors have been used at GANIL in order to perform two of such experiments: i) Secondary beams of neutron-rich Ge, Zn and Ni isotopes around N=40 were produced from the fragmentation of a primary /sup 86/Kr beam, and analyzed by means of the LISE3 spectrometer. For the transitions between the 0/sup +/ ground state and the first 2/sup +/ state, B(E2) values have been extracted from Coulomb excitation cross-section measurement. Some of the obtained results related to the effectiveness of the N=40 spherical sub-shell closure as well as future improvements of the quality of the data are discussed. ii) In-beam gamma -spectroscopy of neutron-rich nuclei around /sup 32/Mg produced by fragmentation of /sup 36/S have been recently performed Gamma decay of relatively higher excited states have been measured in a large number of exotic light nuclei. Preliminary results obtained in a number of even-even nuclei around N=20, such as /sup 20,22/O, /sup 26,28/Ne and /sup 30,32/Mg are presented.