1. Lucie Castets was born in Caen to parents who worked as psychoanalysts, and resided in Caen up until the age of 18.

1. Lucie Castets was born in Caen to parents who worked as psychoanalysts, and resided in Caen up until the age of 18.
Lucie Castets studied at the lycee Charles-de-Gaulle in Caen, and afterwards studied political economy and public law at Sciences Po.
Lucie Castets received a master's degree from Sciences Po and the London School of Economics and studied Chinese at Fudan University in Shanghai, before graduating from the Ecole nationale d'administration in 2013.
Lucie Castets began her career in the French civil service in 2007, working as an assistant to the cultural attache at the Consulate-General of France in Shanghai between 2007 and 2008.
Lucie Castets became involved with the World Bank in 2011, primarily working on projects involving financial intelligence.
Between 2018 and 2020, Lucie Castets headed a section at Tracfin within the Ministry of Economics and Finance, the intelligence agency responsible for combating illegal financial circuits, money laundering, and the financing of terrorism.
In 2020, Lucie Castets joined the administration of mayor of Paris Anne Hidalgo, becoming an economic advisor.
Between 2014 and 2017, Lucie Castets was a lecturer of economics at Sciences Po.
Lucie Castets was a member of the Socialist Party between 2008 and 2011, when she was a supporter of Martine Aubry and the Union of the Left.
Lucie Castets has worked for the Besoin de gauche movement for Pierre Moscovici and for the Point d'ancrage think tank.
Lucie Castets entered elected politics for the first time after being selected to stand as a candidate for the Socialist Party in the 2015 regional election in Normandy, although she was not elected.
Lucie Castets left the Socialist Party in 2011, due to disagreements with the political direction that Francois Hollande took the party.
In 2021, Lucie Castets cofounded the Nos services publics collective, which seeks to "highlight dysfunctions and make proposals" to improve public services in France.
Lucie Castets received public attention in 2022, when she questioned Stanislas Guerini on the television program Ce soir about the unwarranted use of consulting firms.
In July 2024, Lucie Castets was nominated by the New Popular Front as their candidate for prime minister of France, in the aftermath of the 2024 legislative election in which the NFP won the most seats but not a majority.
Lucie Castets rejected forming a coalition with Macron's Ensemble group due to what she said were profound disagreements, and urged Macron to accept her nomination.
Lucie Castets is married to a woman and they have a child.
Lucie Castets played tennis for about ten years, and served as ball girl at the French Open at the age of 15.