Over the past decade, a growing literature has shed light on the rise of inequalities at the very top of the income distribution. There is no doubt that such extreme inequalities do threaten social cohesion and that some public policies are needed in order to tackle this issue. The design of these policies requires to set some benchmarks that could serve, at least, as a guideline to promote efforts towards the reduction of inequalities. In the same way that the fight against poverty can usefully benefit from researchers’ efforts to define poverty, it is arguable to think that the fight against extreme inequalities should also greatly benefit of some definition of rich people. However, very little attention has been warranted up to now to the definition of the rich in the academic literature. The purpose of the paper is to try to fill this gap. It draws on some previous definition of an affluence line and proposes some estimates for three countries (France, Ireland and the UK).