Also additional Higgs bosons much lighter than the state discovered at 125 GeV must be considered. Such bosons could be feasible e.g. in the context of the Next-to-Minimal Supersymmetric Model (NMSSM). We are investigating a scenario where a pair of light Higgs bosons could appear through the decay of the known Higgs boson at 125 GeV. If the mass of the light bosons is below the beauty threshold, each would decay dominantly into a pair of τ leptons. The analysis has been successfully completed. No signal has been observed, and upper exclusion limits on the production cross section of such light Higgs bosons have been set.