Population issues have sparked and still have the potential to spark heated debates in France – witness the Ined controversy over fertility data in the early 1990s – as well as articles that present population trends in a tendentious or even fanciful way. This paper gives several examples relating to human longevity, fertility and the size of the French population. Wrong data have polluted and obscured the social debate on the issue of population ageing. In recent years, however, specialists seem to have taken a more reasonable approach to these population issues. The author, involved in past criticism of Ined, reviews these issues here in the hope that these kinds of mistakes will not be repeated.