Using time-resolved small-angle light scattering, we present the first experimental evidence that a semidilute polymer solution successively subjected to a high-strain-rate shear flow followed by a low-strain-rate shear flow displays concentration fluctuation enhancement and fluctuation reduction (Maxwell effect), respectively. During the Maxwell fluctuation reduction, the flow-induced intermediate scattering peaks present in the structure factor at high strain rates are eliminated and the scattering patterns rotate toward a direction at 90-degrees with the flow direction. The Maxwell rotation and stretching of the shear-enhanced fluctuations and the corresponding pattern orientation angle are satisfactorily described by the so-called Maxwell construction applied to the Helfand-Fredrickson structure of the shear-enhanced fluctuations.