Jeanne Moreau:
(Paris, January 23, 1928 – Paris, July 31, 2017) . French actress, known for her roles in numerous feature films, including Les Amants, Les Liaisons dangereuses 1960, and Jules et Jim. She was awarded many prizes, including three César Awards, the most important French film award.

Freedom is being able to choose the one whose slave you will be.

This quote refers to a classic idea in political philosophy:
absolute freedom is impossible when living in society, because it would inevitably clash with the freedom of others. True freedom, therefore, does not consist of escaping all forms of submission or dependence, but of being able to choose to whom or what one submits—a law rather than a tyrant, a freely given commitment rather than an imposed constraint. In other words: one is never completely free from a form of “slavery” (in the broad sense—attachment, obedience, dependence), but one can at least choose which one.
Origin:
No verifiable primary source could be identified: no dated interview, no film, no book, no specific speech. The phrase circulates only on online quote sites (Dicocitations, Ma-Citation, Babelio, etc.), which copy each other without ever tracing it back to an original source. The underlying idea, however, is much older and aligns with social contract theories (Hobbes, Rousseau), where freely chosen submission to the law is presented as the very condition of freedom in society.
Author:
Commonly accepted attribution:
Jeanne Moreau (French actress, singer, and director, 1928–2017).
This attribution is consistent and repeated on numerous websites, but remains unverified due to the lack of a primary source. It could be a phrase actually spoken by her (in a non-digitized interview, for example), or an apocryphal quote—a very common phenomenon where a well-turned phrase is retroactively attributed to a famous person to gain credibility. As a precaution, I recommend presenting it as “quote attributed to Jeanne Moreau” rather than as a definitive quote, unless you can locate it in a reliable biographical source (memoirs, interview collection).