[en] The 12. colloquium of the young members of the French society of nuclear energy (SFEN) brought together about 200 young French and foreign professionals, experts and students. The subject of the colloquium was the European energy choices and the problem of wastes production. This article summarizes the content of the conferences given on December 9 about the management of energy and wastes: status of world energy resources and consumption; fossil fuel reserves; status of development of renewable energy sources; the economical and environmental efficiency of nuclear energy; the wastes generated by the energy activities in general and by the nuclear energy in particular: the Swedish approach of the nuclear waste management problem, the Russian nuclear wastes, the management of municipal wastes in Belgium; the bio-energies (combustion, fermentation, gasification); and the future prospects of the evolution of energy sources. (J.S.)