Sunshade system for use in a vehicle roof assembly, capable of opening or at least partly closing an opening below the vehicle roof assembly, said sunshade system comprising: a flexible sunscreen having at least a main part with two opposite lateral side edges (5, 5'), a leading edge and a trailing edge, a winding shaft for winding and unwinding the flexible sunscreen at its trailing edge, an operating beam attached to the leading edge of the flexible sunscreen guiding strips (10, 10') laterally extending along, and attached to, each of lateral side edges (5, 5') of the main part and each of the guiding strips (10, 10') comprising an inwardly foldable part (11, 11') capable of being folded inwardly towards a longitudinal centreline of the sunshade system in an acute angle with a main part of each of the guiding strips (10, 10') and being folded flat in the same plane as the main part when the flexible sunscreen is wound up onto the winding shaft and a first hinge part extending in longitudinal direction of said strip (10, 10'), whereby the first hinge part is formed as a depression (13, 13') made in the guiding strips (10, 10') and whereby each inwardly foldable part (11, 11') is connected to the remainder of the guiding strip (10, 10') by means of said first hinge part, and two opposed longitudinal guides (14, 14') for retaining therein in a transverse direction and slidably guiding therein in a longitudinal direction, at least the inwardly foldable parts (11, 11'), and at least a part of the main part of the guiding strips (10, 10'), said guides (14, 14') being provided with locking members and with guide chambers for engaging at least the inwardly foldable part (11, 11') of the flexible sunscreen for preventing said inwardly foldable parts (11, 11') from laterally moving out of the longitudinal guides (14, 14') when the flexible sunscreen is at least partly unwound, characterized in that each guiding strip (10, 10') is made of thermoplastic material and comprises at least a second hinge part extending parallel to the first hinge part, longitudinally along the length of the guiding strip (10, 10') to form an opposite foldable part (18, 18'). a flexible sunscreen having at least a main part with two opposite lateral side edges (5, 5'), a leading edge and a trailing edge, a winding shaft for winding and unwinding the flexible sunscreen at its trailing edge, an operating beam attached to the leading edge of the flexible sunscreen guiding strips (10, 10') laterally extending along, and attached to, each of lateral side edges (5, 5') of the main part and each of the guiding strips (10, 10') comprising an inwardly foldable part (11, 11') capable of being folded inwardly towards a longitudinal centreline of the sunshade system in an acute angle with a main part of each of the guiding strips (10, 10') and being folded flat in the same plane as the main part when the flexible sunscreen is wound up onto the winding shaft and a first hinge part extending in longitudinal direction of said strip (10, 10'), whereby the first hinge part is formed as a depression (13, 13') made in the guiding strips (10, 10') and whereby each inwardly foldable part (11, 11') is connected to the remainder of the guiding strip (10, 10') by means of said first hinge part, and an inwardly foldable part (11, 11') capable of being folded inwardly towards a longitudinal centreline of the sunshade system in an acute angle with a main part of each of the guiding strips (10, 10') and being folded flat in the same plane as the main part when the flexible sunscreen is wound up onto the winding shaft and a first hinge part extending in longitudinal direction of said strip (10, 10'), whereby the first hinge part is formed as a depression (13, 13') made in the guiding strips (10, 10') and whereby each inwardly foldable part (11, 11') is connected to the remainder of the guiding strip (10, 10') by means of said first hinge part, and two opposed longitudinal guides (14, 14') for retaining therein in a transverse direction and slidably guiding therein in a longitudinal direction, at least the inwardly foldable parts (11, 11'), and at least a part of the main part of the guiding strips (10, 10'), said guides (14, 14') being provided with locking members and with guide chambers for engaging at least the inwardly foldable part (11, 11') of the flexible sunscreen for preventing said inwardly foldable parts (11, 11') from laterally moving out of the longitudinal guides (14, 14') when the flexible sunscreen is at least partly unwound, characterized in that each guiding strip (10, 10') is made of thermoplastic material and comprises at least a second hinge part extending parallel to the first hinge part, longitudinally along the length of the guiding strip (10, 10') to form an opposite foldable part (18, 18').