Citizens are regularly asked to do their share to reduce the environmental impact of their daily activities. A survey found that the households most inclined to change their behaviour are those already convinced of the importance of environmental issues. By focusing on disparities between different categories of the population, the survey shows that the ability to act in favour of the environment has more of an influence on households’ behaviour than their income level. Many surveys show that they take account of environmental criteria in their everyday choices, but numerous factors hinder them from effectively changing their habits. Whether at home, travelling or shopping, they are more or less intensely involved in favour of the environment by adjusting to the structural constraints they encounter.