A blade in which the aerodynamic profiles of a blade root, a blade neck and a central part of a profiled zone of the blade respectively comprise a leading edge section and a trailing edge section that are symmetrical to each other relative to an axis of symmetry. The present disclosure also concerns a method for constructing such a blade. The axis of symmetry is perpendicular to a segment connecting the leading edge to the trailing edge of each profile and is positioned in the middle of the segment. An intermediate upper surface section and an intermediate lower surface section connect the leading edge section and the trailing edge section in order to respectively form a lower surface of the aerodynamic profile.