Climate change and local anthropogenic disturbances deeply affect the water and carbon fluxes of peatlands. This may trigger carbon fluxes to surface waters and the atmosphere, thus leading to positive feedback for global warming. It is therefore crucial to better estimate carbon fluxes between peatlands and the atmosphere and to delineate their major controlling constraints. To achieve this goal, we studied the functioning of a temperate midmountain peatland located in the French Jura Mountains, named the Frasne peatland. Thanks to high-frequency eddy-covariance and hydrometeorological monitoring over 2.5 years, we built a conceptual production-emission model of CH4 fluxes with the atmosphere. This model highlights that water-carbon interactions in the peatland depend on local biotic and abiotic factors but also on hydrological processes at the watershed scale. CH4 fluxes also showed different responses from interannual to diurnal scales. In particular, we found an outstanding diurnal cycle for CH4 with the highest fluxes at night and lower ones at midday. In addition, the mid-day fluxes were negative in spring, highlighting larger oxidative processes than CH4 production attributed to photosynthesis activity (i.e., soil oxygen penetration and endosymbiotic methanotrophs of Sphagnum). To characterize the biological processes involved in the CH4 dynamic and in particular how they favor or limit CH4 production, we organized an interdisciplinary field campaign in June 2023 that included microbiological characterization (membrane lipid) with hydrogeochemical analyses of peat pore water (major elements, DOC (quantity and quality), CO2, CH4, δ18OH2O-δ2HH2O, δ13CDIC, δ13CDOC, δ13CCH4, δ2HCH4, δ13CCO2) along upstream-downstream and surface-depth gradients.