A packaging machine for packs of containers including a horizontal conveying means for the containers grouped as packs, a means for supplying flat paperboard sheets at the bottom side of the containers, wherein the containers are transported in a standing manner on the paperboard sheet, a means for folding upward front and back, in the transport direction, edge portions of the paperboard sheet, each of which extends beyond the footprint of the pack, at least two opposing lateral guide elements for folding upward lateral edges of the paperboard sheet extending laterally beyond the footprint of the grouped containers, wherein at least portions of the guide elements exert a defined pressing force on the upward-folded edges of the paperboard sheet and the side faces of the pack, and an adhesive is provided with edge portions of the lateral edges overlapping with front and/or back edges of the paperboard sheet.