Three-way valve with two flaps comprising common control means (9) for the two flaps and actuation means (12, 13, 50) arranged each to drive, pivotwise, one of the two flaps, from one to the other of its open and closed position of one of the pathways, with a temporal phase-shift, such that, in a first stage the common control means pivot the second flap, the first flap remaining in a waiting position under the action of return means, and in a second stage, said control means, while continuing to pivot the second flap, begin to pivot the first flap, characterized in that said second actuation means (12, 50) comprises a return driving means (71) making it possible to pivot the second flap (5) to its first position under the action of the common control means (9) in the case of a failure of said return means.