Fifrelin4Geant4 is an interface library that allows to use nuclear de-excitation files created with FIFRELIN code within a Geant4 application. Fifrelin4Geant4 can easily be used with minor modifications depending on the dataset format with: 155Gd(nth,g) and 157Gd(nth,g) de-excitation cascade datasets for neutrino experiment with Gd-loaded detectors (https://doi.org/10.5281/zenodo.6861341) -- STEREO collaboration. the FIFRADINA datasets: Al(nth,g) in Al2O3, Si(nth,g) in Si, Ge(nth,g) in Ge, W(nth,g) in CaWO4 for nuclear recoil calibration of cryogenic detectors (https://doi.org/10.5281/zenodo.7936552) -- CRAB collaboration. GitLab: http://gitlab.com/lthullie/fifrelin4geant4