Carbon nanomaterials are widespread in the atmospheric aerosol as a result of the combustion processes and their extensive industrial use. This has raised many question about the potential toxicity associated with the inhalation of such nanoparticles, and its incorporation into the lung surfactant layer. In order to shed light on the main physical bases underlying the incorporation of carbon nanomaterials into lung surfactant layers, this work has studied the interaction at the water/vapor interface of carbon nanosheets (CN) with Langmuir monolayers of 1,2-Dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC), with this lipid being the main component of lung surfactant layers and responsible of some of the most relevant features of such film. The incorporation of CN into DPPC Langmuir monolayers modifies the lateral organization of the DPPC at the interface, which is explained on the basis of two different effects: (i) particles occupy part of the interfacial area, and (ii) impoverishment of the lipid composition of the interface due to lipid adsorption onto the CN surface. This results in a worsening of the mechanical performance of the monolayers which may present a negative impact in the physiological performance of lung surfactant. It would be expected that the results obtained here can be useful as a step toward the understanding of the most fundamental physico-chemical bases associated with the effect of inhaled particles in the respiratory cycle.