The term diversity is polysemous, and definitions allow it to refine its meaning. The concepts proposed are cross-cutting since universalism, equal opportunities, secularism, or pluralism are principles common to all democratic societies.

Diversity does not mean the same thing depending on the adjective attached to it (political, cultural, religious, ethnic), the prefix that is added to it (biodiversity, super-diversity) or the periphrase used (territories, learning ). Diversity nonetheless remains synonymous with variety, difference, richness, but also otherness and citizenship. It is also the positive face of discrimination when the difference is not recognized and respected with the negative notions of stereotypes, clichés or "labeling" attached to it. The theoretical and institutional foundations of diversity are directly linked to the principle of republican universalism which allows the recognition and respect of differences and minorities from an anthropological analysis and a legal approach.

The anti-discrimination system put in place in Europe since the early 2000s is also explained and detailed. Diversity was given a new lease of life with the entry of ten new member countries into the European Union in 2004. The Charter of Fundamental Rights adopted by Europe in 2010 also refers to human and citizen rights. Like any European directive, this anti-discrimination device was transposed into national law between 2000 and 2010, respecting its spirit in order to provide all European countries with the same bases. The French case is explained on the basis of the assessment report published by the defender of rights (2013-2020) to help fight more effectively against discrimination and hate speech (racist, xenophobic, misogynist, homophobic…). A particular case of xenophobia is proposed: “romophobia”.

Thirdly, a comparative approach to strategies for promoting diversity is proposed in particular in Europe where it is more focused on equal opportunities and the legal approach to combating discrimination and in the United States where we are talking about “positive discrimination” which can seem like an alliance of words in a French or European conception which is part of the same logic as “positive actions”.