How are social inequalities in tobacco use evolving in France across different age groups and generations? To answer this question, data from the Health Barometer survey, collected in 2010 from 27,653 individuals, were used to retrospectively reconstruct the smoking history of three birth cohorts (1941–1955, 1956–1970, and 1971–1985). Changes in smoking inequalities were examined by comparing smoking prevalence rates calculated at each age according to educational attainment, sex, and generation, and then using a relative inequality index estimated via logistic regressions. The results show that after having been more common among those with higher levels of education, smoking has declined in these groups, while it continues to rise among those with lower levels of education. This analysis also confirms a one-generation lag among women compared to men in the spread of smoking, even though prevalence levels are now high for both sexes. The significance of social inequalities regarding smoking is evident at young ages, across all cohorts and for both genders. For older cohorts, inequalities narrow over the course of life until they reverse among women. For the most recent cohort, inequalities remain high throughout the life cycle and tend to widen after age 25 for women. Based on these findings, it may be effective to tailor tobacco prevention policies to specific social groups and life stages, and in particular to focus efforts on preventing initiation into smoking among those with lower educational attainment.[author’s abstract]