Fournier was born in Romorantin in Loir-et-Cher to an electrician father who became a physiotherapist[1] and a mother who worked as a teacher.

[4][5][6] From July 2015 to December 2022, he is one of the vice-presidents of the Centre-Val de Loire region alongside the majority of François Bonneau (PS).

[3][2][7] At the regional council, he was mainly involved in the social and solidarity economy, community life, and democratic participation, climate and ecological transition.

[8] He returns to Tours at the beginning of 2022 for personal reasons and is a candidate for the nomination of EELV for the legislative elections.

[9][3] Fournier becomes the candidate designated by the New Ecological and Social People's Union in Indre-et-Loire's 1st constituency for the 2022 French legislative election, he topped the poll in the first round, with 39.6% of the votes cast, ahead of the incumbent MP Philippe Chalumeau who was running for the Ensemble group.