French law states a clear position against the use of the ethno-racial categories. Since the UNESCO program drawn up after the Second World War with the collaboration of important French intellectuals, Moral values and Science are interlaced in official speeches to deny any racial reality. From this point, the crucial debate among politicians and legal scholars became the deletion of the word "race" in legal texts or the unconstitutionality of ethno-racial statistics, even for generous purposes i.e. fight against racism and discriminations. In the medical field, nothing similar to the NIH and FDA policies on the integration of minorities in clinical research has been adopted. French law and the French legal culture thus appear as a counter-model compared with the US situation. Consequently, one might think that France would avoid the difficulties that American lawyers are currently facing because of the combined action of affirmative action policies and scientific uses of ethno-racial categories (in human population genetics, pharmacogenomics or prevention medicine). Nevertheless, a closer look closer reveals a more complex reality. Not only some French Medical Agencies used ethno-racial categories as an approximation for human differences in a few technical documents, but also some Court orders show that French judges have an ambivalent relationship with ethno-racial references. By gathering elements from recent judicial decisions regarding health product liability, proof in criminal trial or civil identity case, we may consider, firstly, that judges do not ignore neither the persistence of ethno-racial categories in science and in medicine nor the approximations and scientific uncertainty included in this approach; secondly, that they voluntarily try to minimize uncertainties and problematic issues and endorse ethno-racial references in a half-scientistic, half-pragmatic approach. By doing so, they strengthen the fallacious idea that the current medical and scientific uses of racial categories is not questionable and throw the French legal system into confusion.