A sunshade assembly includes a flexible sunscreen, a rotatable winding shaft for winding and unwinding the sunscreen and two opposed guides for cooperation with two opposed longitudinal edges of the sunscreen. Each guide extends longitudinally in a curved manner in a plane which substantially is perpendicular to the sunscreen and in parallel to the respective longitudinal edge of the sunscreen. Longitudinal edge sections of the sunscreen are less stretchable than the remainder of the sunscreen and are tensioned in the longitudinal direction of the sunscreen.