In the last decade, research has shown that word processing is influenced by the lexical and semantic features of words. However, norms for a crucial semantic variable—that is, conceptual familiarity—have not been available for a sizeable French database. We thus developed French Canadian conceptual familiarity norms for 3,596 nouns. This enriches Desrochers and Thompson’s (2009) database, in which subjective frequency and imageability values are already available for the same words. We collected online data from 313 Canadian French speakers. The full database of conceptual familiarity ratings is freely available at http://lingualab.ca/fr/projets/normes-de-familiarite-conceptuelle. We then demonstrated the utility of these new conceptual familiarity norms by assessing their contribution to lexical decision times. We conducted a stepwise regression model with conceptual familiarity in the last step. This allowed us to assess the independent contribution of conceptual familiarity beyond the contributions of other well-known psycholinguistic variables, such as frequency, imageability, and age of acquisition. The results showed that conceptual familiarity facilitated lexical decision latencies. In sum, these ratings will help researchers select French stimuli for experiments in which conceptual familiarity must be taken into account.