Method for treating a cut-out intended to form, after folding-gluing, a folded flattened box, comprising the following steps: a) supplying a substantially flat cut-out comprising a right edge, a left edge, a front edge, a rear edge, a right longitudinal groove and a left longitudinal groove, the right longitudinal groove and the left longitudinal groove delimiting, with the right edge and the left edge at least three flaps among which a right flap, a left flap and a central flap, b) applying of adhesive in a zone of the right flap adjacent to the right edge and/or in a zone of the left flap adjacent to the left edge, in such a way that adhesive is present in an overlapping portion between the right flap and the left flap, c) folding to 180° of the right flap around the right longitudinal groove in the direction of the central flap, and folding to 180° of the left flap around the left longitudinal groove in the direction of the central flap, d) closing of the folded right flap and of the folded left flap which are located one above the other at least in the overlapping portion, e) checking the position of the right edge and of the left edge and comparing this actual position with a predetermined position so as to determine a position deviation, f) when the position deviation exceeds an admissible deviation value, carrying out of the following substeps before the adhesive sets: f1) immobilising of the central flap, then f2) gripping of the upper surface of the folded right flap and of the folded left flap by respectively at least one vacuum suction cup (21, 23, 24, 26), and f3) correcting of the position of the left flap and/or of the right flap by displacement of the vacuum suction cup (21, 23, 24, 26), g) applying of pressure between the right flap and the left flap in the overlapping position until the adhesive sets, and h) releasing of the central flap, of the right flap and of the left flap. a) supplying a substantially flat cut-out comprising a right edge, a left edge, a front edge, a rear edge, a right longitudinal groove and a left longitudinal groove, the right longitudinal groove and the left longitudinal groove delimiting, with the right edge and the left edge at least three flaps among which a right flap, a left flap and a central flap, b) applying of adhesive in a zone of the right flap adjacent to the right edge and/or in a zone of the left flap adjacent to the left edge, in such a way that adhesive is present in an overlapping portion between the right flap and the left flap, c) folding to 180° of the right flap around the right longitudinal groove in the direction of the central flap, and folding to 180° of the left flap around the left longitudinal groove in the direction of the central flap, d) closing of the folded right flap and of the folded left flap which are located one above the other at least in the overlapping portion, e) checking the position of the right edge and of the left edge and comparing this actual position with a predetermined position so as to determine a position deviation, f) when the position deviation exceeds an admissible deviation value, carrying out of the following substeps before the adhesive sets: f1) immobilising of the central flap, then f2) gripping of the upper surface of the folded right flap and of the folded left flap by respectively at least one vacuum suction cup (21, 23, 24, 26), and f3) correcting of the position of the left flap and/or of the right flap by displacement of the vacuum suction cup (21, 23, 24, 26), f1) immobilising of the central flap, then f2) gripping of the upper surface of the folded right flap and of the folded left flap by respectively at least one vacuum suction cup (21, 23, 24, 26), and f3) correcting of the position of the left flap and/or of the right flap by displacement of the vacuum suction cup (21, 23, 24, 26), g) applying of pressure between the right flap and the left flap in the overlapping position until the adhesive sets, and h) releasing of the central flap, of the right flap and of the left flap.