In France, no. The electricity mix reaching your meter is strictly the same regardless of your commercial contract: the pooled national grid, already very low-carbon thanks to nuclear power (50-60 gCO₂/kWh). Signing a "green" contract changes accounting on paper, rather than physics in the atmosphere. International standards now publish both calculation methods in parallel (with and without the contract), precisely to avoid accounting optimisation. What reduces emissions is consuming less electricity, rather than buying a different colour.
Read the source article: Reduce your Bilan Carbone®: 4 levers and a 3-year plan