The conventional hydrogen production process is accompanied by the production of large amounts of carbon dioxide, which affects the application of hydrogen energy. Therefore, it is necessary to monitor the carbon dioxide content of hydrogen gas. Due to their excellent optical properties, all-inorganic perovskites can be made into photoluminescence sensors for monitoring gas concentrations. However, toxic lead halide perovskites are limited in photoelectric applications due to their instability and other drawbacks. Perovskites have rarely been studied for broadband luminescence in the mid-infrared range. Herein, this work reports on Dy3+/Er3+ co-doped Cs3Bi2-m-nErmDynBr9-ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) perovskite fluorine composite glass, which can radiate a broadband mid-infrared luminescence located at 3 µm, covering the characteristic absorption peak of CO2 at 2.7 µm. A CO2 monitoring device is built based on this feature. The use of Bi3+ to replace Pb2+ to form Cs3Bi2Br9 reduces the toxicity of perovskites. The dense and inert nature of the glass is used to isolate the lead-free perovskite Cs3Bi2Br9 from the external environment, thereby improving stability. The addition of Cs3Bi2Br9 not only decreases the phonon density of states in the glass matrix but also changes the local field around the Er and Dy ions. The luminescence of rare earth ions in the mid-infrared is thus enhanced. Cs3Bi2-m-nErmDynBr9-ZBLAN perovskite fluorine composite glass is a promising candidate for future mid-infrared emitting materials due to its non-toxicity and broadband mid-infrared luminescence at 3 µm.