Very few documents allow historians to see Robespierre at work as a lawyer. His professional correspondence, his petitions, consultations, pleadings and other documents related to his profession have practically all disappeared, with the exception of his factums (or legal briefs), almost all of which have been preserved. This exceptional corpus of twelve printed legal briefs allows us access to an aspect of his work as a defence lawyer, that of author of factums, which constitute a veritable legal genre. By studying them, it is possible to analyse the techniques used by Robespierre to attempt to make a case famous and to win over both recipients of these documents, namely the judges and the public. What language should be used to speak to them? How were they to be won over? How was the client to be guaranteed a favourable judgement and public esteem? The answer lay in the development of arguments of law and of fact, of course, but also in the way in which they were developed. Narrative strategies, the use of pathos, the possible choice of a rupture strategy which called into question the legitimacy of the lower courts and the relevance of the law in force, endorsed by the ethos of the lawyer for “the poor” give Robespierre’s writing its full force.