International audience ; Lacan uttered reserves relative to the reception of his thesis and will be reluctant to its republication. Lacan will go back and forth then leave some of the authors who inspired him. However, he always had the concern to teach the psychiatrists, somehow or other.We shall try to determine the conditions of the doctoral examination of Lacan. We would also try to specify the reception of his thesis, to replace it in its context. We shall aim at finding what Lacan was able to say himself about it on several occasions.Search for references to the thesis of Lacan, confrontation of historical data, analysis and comments of texts. The discussion concerns in particular the academic and medical career of Lacan, his motivation to enter it or his aspiration to step out of it and open up to other circles. So, he indicated having made an error about the thesis. We shall try to envisage the diverse modalities where it can lie and what implications she may have had.We discovered that the student file of Lacan is missing. We found two reports underestimated of that time, one of the Lucien Rouquès and other one of Henri Wallon which was probably at the origin of their relations. We also learnt by the way that Lacan obtained the prize Baillarger.There are still points to be clarified concerning Lacan and the psychiatry. It however gave fruitful debates. And it has at least brought Lacan, through his thesis and his patient Aimée, to meet psychoanalysis. ; Nous avons tenté de déterminer les conditions de passation de la thèse de Lacan. Nous l’avons replacée dans son contexte. Lacan a émis des réserves relatives à l’accueil de sa thèse et sera réticent à sa republication. Il a indiqué avoir fait une erreur à propos de sa thèse. Nous avons envisagé diverses modalités où elle peut résider et ce qu’elle a pu avoir comme implications. Nous avons découvert que le dossier étudiant de Lacan est manquant. Nous avons retrouvé deux comptes rendus méconnus de l’époque, l’un de Lucien Rouquès et l’autre d’Henri Wallon ...