Madame Clothilde works the café in Les Halles where Giovanni takes David, Jacques, and Guillaume. She adores Giovanni, and he introduces her to everyone. She is particularly taken with David. Giovanni insists that Guillaume buy everyone drinks, and Guillaume and Madame Clothilde discuss business and French affairs while they drink champagne.
When we first encounter Madame Clothilde, this is how David remembers her:
Behind the counter sat one of those absolutely inimitable and indomitable ladies, produced only in the city of Paris, but produced there in great numbers, who would be as outraged and unsettling in any other city as a mermaid on a mountain-top. All over Paris they sit behind their counters like a mother bird in a nest and brood over the cash-register as though it were an egg. Nothing occurring under the circle of heaven where they sit escapes their eye, if they have ever been surprised by anything, it was only in a dream – a dream they long ago ceased having. They are neither ill- nor good-natured, though they have their days and styles, and they know, in the way, apparently, that other people know when have to go to the bathroom, everything about everyone who enters their domain. (1.3.35)