A rail guide that has at least one rail pair consisting of a floor rail (22) and a seat rail (24). The seat rail (24) has connectors (30) for fastening a seat frame to be arranged above the rail pair. The rails can be moved relative to each other in a longitudinal direction along a movement path (20). The floor rail (22) and the seat rail (24) are curved by the same circular radius of curvature (42) that ranges between 1,500 and 3,000 mm, in particular between 1,800 and 2,500 mm. The center point of curvature (44) is on the side of the rail pair facing away from the seat frame. The rail guide is a longitudinal adjustment device having a stationary spindle (52) and an associated spindle nut (54) that is longitudinally movable thereon, the spindle (52) being curved at the same circular radius of curvature (42). Also described is a suitable method for producing said curved rails by at least one stamping mold (68) or by bending strips (96).