Complete γ-decay in the 12 C (12 C ,γ)24 Mg and 12 C (16 O ,γ)28 Si reactions has been measured at energies close to the Coulomb Barrier using the DRAGON spectrometer and its associated BGO γ-array at the TRIUMF facility. The experimental data show an important feeding of doorway states around 10-11 MeV in both reactions. Comparisons with simulations allow to extract the full capture cross section and the main spin involved in the process. Different models are confronted to the results : completely statistical, semi-statistical with an unique entrance spin and cluster. The resolution of the BGO enables to eliminate a fully statistical scenario but is not enough to disentangle the two remaining scenarii. It is shown that the future PARIS array composed of the recently developed LaBr 3 scintillators will have capabilities to distinguish between these two scenarii.