avocat au Conseil d'Etat et

à la Cour de cassation

The job of a supreme-court lawyer is to reason with, explain, and persuade

by Guillaume Hannotin


With its hypotheses and conclusions, a legal rule is a statement, like a mathematical theorem, that serves to resolve conflicts.

We start with the postulate that “the client is always right”, which does not mean they are objectively right, which we will argue without fail in the petition, nor that the court or authority is certain to agree with them, but that clients have their reasons for believing they are right, their side of the story, which they defend in good faith.

« Reasoning is a question of feeling », an experienced supreme-court judge told me once. Our goal is to take the decision maker from a position of possibly sympathizing with your cause to understanding your point of view and agreeing with you. That way, we increase the chances that the law we argue subjectively on your behalf will become the objectively established rule.

With its hypotheses and conclusions, a legal rule is a statement, like a mathematical theorem, that serves to resolve conflicts. But unlike a mathematical theorem, a legal rule never stands alone, without context. It does not “appear out of thin air”. A legal rule is established in relation to a specific conflict of interests or points of view. It is therefore stated as a site of confrontation that became a frontline, then a border.

Our first job is to determine which legal rules objectively apply to your situation. We then examine how they developed over time to determine which ones may be able to evolve in your favor given your situation compared to those that gave rise to the rules.


Experience teaches that no legal issue is completely new; decision makers are not free to rule as they please. Experience also teaches that while legal issues theoretically fall within narrowly defined fields of law, they actually have several facets. And in our experience, it is extremely rare for a legal issue to be unrelated to other fields, such as the social or hard sciences, politics, or history, or the practices of other legal systems.

We therefore start by making sure the decision maker is not free to innovate as they please by identifying the preexisting objective, almost physical constraints they will be under and the key elements that point to the conclusion we want the decision maker to reach. In other words, we draw a map to guide the decision by identifying the topic’s reefs and contour lines and by researching the various facets of law (legal history, Union law, procedural law, etc.) that must be brought to bear to resolve your issue so that we can develop the most persuasive arguments.


We also use the relevant work of historians, sociologists, and scientists—we are avid readers of parliamentary, think tank, and institutional (CESE, French Audit Court, and OECD) reports, and frequently conduct comparative law studies. To make another comparison, like a good surveyor, we follow each line to get the lay of the land and see the connections that will enable us to solve the problem.

The results of our work are presented in uniquely clear, well-developed written or oral arguments that are as captivating as possible.

Guillaume Hannotin