In this chapter, we propose to explore the conditions under which a stringent target of 1.5°C - written into the Paris Agreement in December 2015 – may be fulfilled at a country level, France, while focusing on energy issues. The analysis horizon spans to 2072 in reference to the Club of Rome’s 1972 Limits to Growth publication, 2072 being the neutral target. To this end, we explore the impact of two contrasting lifestyles for France: the first, named digital, represents an individualistic and technological society, whereas the second, named collective, depicts a society with strong social ties and cooperation between citizens. These scenarios are assessed through different models, each one representing a particular aspect: lifestyles, economy and technologies. While technology-oriented energy models usually omit or over-simplify the lifestyle dimension, the proposed approach gives a more coherent framework for the formulation of alternative demand levels. These demands for energy services enrich the scenario-building process and influence not only the economic system, but also the energy system. The digital society involves significant growth of both GDP and the unemployment rate, and does not result in carbon neutrality, whereas the collective society leads to smaller growth of GDP and a decrease in the unemployment rate, but makes it possible to reach a nil carbon target. These results underline the leverage role of lifestyles in attaining carbon neutrality.