A system for orienting slats of a sunshade system for protecting a façade, comprising: - a series of parallel slats each pivoting in both directions about a pivot axis; - and a device for pivotally driving slats that comprises: -- a drive carriage that is movable in translation in both directions along a longitudinal direction orthogonal to the pivot axes of the slats and over a determined path between a first end position to which it is elastically returned and a second end position; -- a mechanism for converting the longitudinal movements of the drive carriage into simultaneous pivotal movements of the slats; -- a controlled actuator of the movements of the drive carriage which comprises a variable-length member made of a shape-memory material, the length whereof varies as a function of its temperature, a first end whereof is connected to a fixed anchoring point, and the other end whereof is connected to the drive carriage; -- means for controlling the variation in the temperature of the variable-length member of the actuator in order to cause movements of the drive carriage between its two end positions; characterized in that the system comprises a controlled block for adjusting the angular orientation of the slats which is movably mounted between: - a retracted position; - and an active blocking position wherein, against an elastic biasing force applied to the drive carriage, the controlled adjustment block immobilizes, directly or indirectly, the drive carriage in an intermediate longitudinal position between its two end positions. - a series of parallel slats each pivoting in both directions about a pivot axis; - and a device for pivotally driving slats that comprises: -- a drive carriage that is movable in translation in both directions along a longitudinal direction orthogonal to the pivot axes of the slats and over a determined path between a first end position to which it is elastically returned and a second end position; -- a mechanism for converting the longitudinal movements of the drive carriage into simultaneous pivotal movements of the slats; -- a controlled actuator of the movements of the drive carriage which comprises a variable-length member made of a shape-memory material, the length whereof varies as a function of its temperature, a first end whereof is connected to a fixed anchoring point, and the other end whereof is connected to the drive carriage; -- means for controlling the variation in the temperature of the variable-length member of the actuator in order to cause movements of the drive carriage between its two end positions; -- a drive carriage that is movable in translation in both directions along a longitudinal direction orthogonal to the pivot axes of the slats and over a determined path between a first end position to which it is elastically returned and a second end position; -- a mechanism for converting the longitudinal movements of the drive carriage into simultaneous pivotal movements of the slats; -- a controlled actuator of the movements of the drive carriage which comprises a variable-length member made of a shape-memory material, the length whereof varies as a function of its temperature, a first end whereof is connected to a fixed anchoring point, and the other end whereof is connected to the drive carriage; -- means for controlling the variation in the temperature of the variable-length member of the actuator in order to cause movements of the drive carriage between its two end positions; - a retracted position; - and an active blocking position wherein, against an elastic biasing force applied to the drive carriage, the controlled adjustment block immobilizes, directly or indirectly, the drive carriage in an intermediate longitudinal position between its two end positions.