The recycling of paper and board (PB) yields economic and environmental advantages compared to primary paper production. However, PB from lightweight packaging (LWP) waste is currently not comprehensively reintegrated into the paper value stream. To develop an adapted recycling process for PB from LWP, PB quantities, qualities, and fluctuations ranges in LWP are required. Currently, no sufficient database is available. Therefore, we developed a methodical approach and conducted a case study to access the PB potential in LWP sorting plants using manual analysis and sensor-based material flow monitoring. Differences resulting from seasonal variations, materials from different settlement structures, and fluctuation ranges in LWP composition over two weeks have been investigated. PB contents in the input of 6.5 wt% (ww) and 5.9 wt% (ww) were determined for winter and summer sampling campaigns, respectively. The PB product stream amounted to 5.7 wt% (ww, winter) and 4.8 wt% (ww, summer). Around 45 wt% (ww) of PB from the PB product stream was classified as misplaced by the consumer and should have been discarded in separate paper collections. Based on the determined PB quantities and qualities, a potential of usable and in the PB product stream available PB in LWP was determined. The technically available and usable PB potential in German LWP waste amounts to 89,000 to 100,000tons per year (average PB yield of around 65 wt% (ww)). The methodical approach can be adapted for sorting plant balances. The results can contribute to developing an adapted recycling process for PB from LWP.