The invention relates to an ORC (Organic Rankine Cycle) for the conversion of thermal energy into electric energy, comprising at least one heat exchanger unit for re-superheating the working fluid by means of the thermovector fluid from the hot source, between the discharge of the first expander and the input of the second expander, and a regenerator unit including a first regenerator and at least one second regenerator for regenerating the working fluid in at least two successive stages, in said first regenerator and at least in said second regenerator respectively, with an additional regenerative heat exchange along the flow line connecting the liquid working fluid output of the second regenerator to the liquid working fluid input of the first regenerator.