The invention relates to a production plant (1), in particular for folding workpieces (2) to be produced from sheet metal, comprising a bending press (3), in particular a press brake, having a press beam (13, 16), at least one bending tool (4), such as a bending punch (5) and bending die (6), which is connected to the press beam (13, 16), and at least one angle-measuring device (46) for determining an angular position of at least one limb (35, 36) of the workpiece (2) formed by a bending operation relative to a reference plane (41, 42). The angle-measuring device (46) comprises at least one inclination sensor (39) having a reference surface (40) and the inclination sensor (39) is mounted by the angle-measuring device (46) so that it can be placed with the reference surface (40) lying in contact with a surface portion of at least one of the limbs (35, 36) of the workpiece (2).