Mathilde is the co-founder of Institut Avant-garde. She is a graduate of the Ecole Normale Supérieure, the Paris School of Economics and the École des Hautes Études en Sciences Sociales. She defended her thesis on financial crises, the accumulation of public debt and sovereign defaults in 2017 under the supervision of Daniel Cohen.

Mathilde Viennot joined France Stratégie in 2019. She has written several papers on the sustainability of our social protection system, green planning and environmental inequalities. Since 2023, Mathilde has been in charge of the social and societal challenges of environmental transition. As such, she contributed to the report by Jean Pisani-Ferry and Selma Mahfouz, The economic implications of climate action, and in particular to the thematic reports on damage and adaptation, sufficiency and distributional issues Social media Publications.