Addressing discrimination within the professional sphere is becoming ever more important in French public debate in both the legal and managerial fields. A number of the 18 grounds of discrimination recognised under French law such as gender and ethnicity have been widely discussed in the scientific literature. However, unlike studies undertaken in English-speaking countries, few French-speaking researchers have explored age discrimination. This issue warrants analysis insofar as the actual economic context has forced governments to encourage more people to remain in the labour market. This objective, however, has proven difficult to achieve. A critical question is whether age-related labour market participation gaps depend on individual characteristics. If not, other factors might come into play, including possible discrimination. First, we review the employment of older workers over time. We then use econometric methods to assess the nature of labour market participation gaps and analyse their relationship with business cycles. With regard to the latter point, our findings reveal differences between men and women