From a 1996 essay by Elisabeth Roudinesco, “Lacan and Derrida in the History of Psychoanalysis”:

The first encounter between Lacan and Derrida took place…at a famous symposium held in Baltimore in October 1966, which, under the auspices of the Center for the Humanities at Johns Hopkins University, assembled some of the most prestigious French and American academics in the fields of the human sciences and of the interpretation of literary texts.

At dinner…Derrida raised questions close to his heart, about the Cartesian subject, substance, and the signifier. While eating coleslaw, Lacan replied that his subject was the same as the one proposed by his interlocutor as an alternative to the theory of the subject. In itself, the remark was not false, but Lacan hastened to add: “You can’t bear the fact that I have already said what you want to say.” Derrida responded without missing a beat: “That is not my problem.”

From Peter Salmon’s An Event, Perhaps: A Biography of Jacques Derrida (2020):

Despite teaching at the same institution, and being aware of each other’s work, Lacan and Derrida had not met until they attended a dinner at the Belvedere Hotel in Baltimore. It was at an event hosted by the conference organizers, with Lacan holding, incongruously, a plate of coleslaw. According to one account by Lacan’s biographer, Elisabeth Roudinesco, the pair immediately exchanged terse words on the Cartesian subject, substance and the signifier, with each claiming the primacy of his own position against the other’s, chronologically and intellectually. Derrida’s own recollection is more mundane. Lacan was concerned with more prosaic matters. Editions du Seuil had decided to bring Écrits out in a single volume and he was concerned that the binding might be insufficient, meaning that it could fall to pieces in the reader’s hands. Lacan quizzed Derrida about what he knew of binding and glue. Derrida recalled the conversation — “You’ll see,” he told me as he made a gesture with his hands, “it’s not going to hold up.” Derrida does not relate any advice he may have offered regarding adhesives.

From Cynthia L Haven’s Evolution of Desire: A Life of René Girard (2018):

Lacan came to the conference early, via New York, where he had made a detour to see the Albert C. Barnes Foundation art collection outside Philadelphia. A graduate student, Anthony Wilden, had trekked to New York for the care and feeding of Lacan, whose English was sketchy.

Lacan was high-maintenance. “He wanted his underwear laundered,” said [Johns Hopkins professor Richard Macksey]. “They were silk and he wanted them hand laundered. He wanted this and he wanted that.” The Girards remembered the underwear, too. They laughed as they recalled the graduate student who took Lacan’s silk shirts and knickers to the laundry. He reported later that when the Chinese managers at the cleaners were warned that they were “fancy” and “special” shirts, they responded by wadding them up and throwing them on the floor, putting the snooty customer in his place, in absentia.

From Lacan’s talk at the 1966 conference, “Of Structure as an Inmixing of an Otherness Prerequisite to Any Subject Whatever”:

When I prepared this little talk for you, it was early in the morning. I could see Baltimore through the window and it was a very interesting moment because it was not quite daylight and a neon sign indicated to me every minute the change of time, and naturally there was heavy traffic and I remarked to myself that exactly all that I could see, except for some trees in the distance, was the result of thoughts actively thinking thoughts, where the function played by the subjects was not completely obvious. In any case the so-called Dasein as a definition of the subject, was there in this rather intermittent or fading spectator. The best image to sum up the unconscious is Baltimore in the early morning.