Renowned for his experience in corporate, stock exchange, and financial litigation and in white-collar criminal law, Arthur Dethomas is a member of the Club des Juristes (a French legal think-tank). Arthur has developed a recognized competency in complex corporate cases before the French commercial courts and represents clients before courts as well as regulatory authorities. He has been involved on numerous internal investigations and has substantial experience representing clients in cross-border matters, including insider trading, financial fraud and the Foreign Corrupt Practices Act.

According to the Chambers & Partners guide "Arthur Dethomas receives very positive commentary from clients who 'have only positive things to say about him; he is extremely competent, very well known in the market and calm and measured in his work. He is highly experienced in shareholders' dispute and financial liability claim" and "wins praise for his ability to design and execute strategies."

He is recommended by Legal 500 as being "the 'precise and highly skilled" Arthur Dethomas 'ranks among the best of his generation' and 'equally at ease in the courtroom as in the boardroom. In June 2019 he was named "lawyer of the year" in litigation by French magazine Option Droit & Affaires.

Arthur is licensed in Paris and in New York. He began his career at an international commercial law firm, before joining an international business law firm where he was elected to the partnership in 2007. In 2013, he founded a highly renowned litigation boutique firm. He was appointed Premier Secrétaire de la Conférence of the Paris Bar in 2003.

Arthur has a master degree in Business Law (University of Paris X) and an LL.M. from Washington College of Law (A.U.). He is fluent in French and English. A former lecturer in law at the University of Phnom Penh, Cambodia (1998-1999), he also speaks Khmer.

He teaches a class in Financial regulation at Sciences-Po Paris.