Many studies have analyzed the energy mix at national and continental scales, suggesting different low-carbon mixes for future energy systems. While there is abundant literature on the energy mix for different sectors, fewer studies deal with the impact of sector-coupling on achieving the goal of deep decarbonization, with limited representation of emerging low-carbon options and incomplete coverage of the main energy sectors. We develop an integrated optimization-of-dispatch and investment model for the whole energy sector, enabling full sector-coupling, and we apply this model to France for the year 2050. Our results suggest that a robust social cost of carbon of €300/tCO 2 will achieve carbon-neutrality, with a high proportion of renewables on the supply side (> 80% of primary energy production). A fully electrified heat sector and a highly gas-dependent transport sector fueled with renewable gas help reaching carbon-neutrality under the most cost-optimal conditions.