Champagne wines are complex hydroalcoholic mixtures supersaturated with dissolved carbon dioxide (CO2). During tasting, while serving the champagne in a glass and for the few minutes that follow, the headspace of the glass is progressively invaded by many chemical species, including gas–phase CO2 (likely to disrupt the perception of the wine’s bouquet beyond a certain threshold). Real-time monitoring of gas–phase CO2 was performed through tunable diode laser absorption spectroscopy along a multipoint network in the headspace of two champagne glasses showing distinct shapes and volume capacities (namely, the standard 21 cL INAO glass and the brand new 45 cL ŒnoXpert glass, designed by the Union of French Oenologists as a universal glass for the tasting of still and sparkling wines). From the start of the pouring stage and during the several minutes following, a kind of glass type-dependent CO2 footprint was revealed in the headspace of glasses, which was discussed based on the glass geometry and headspace volume. For an identical volume of champagne dispensed in both glasses, the headspace of ŒnoXpert was found to retain gaseous CO2 more efficiently over time than INAO glass does. Therefore, and extrapolating to aromatic compounds, the chemical space of the ŒnoXpert glass should be better preserved throughout the tasting than that of the INAO glass. Moreover, by reducing the volume of champagne served in the glass, the time-dependent CO2 footprint is significantly reduced in the glass headspace, thus reducing the risk of carbon dioxide burn during tasting.