Improvisation and performance are not traditionally associated with the comics form, but experiments with them are increasingly found in the area of alternative, or smallpress, comics. This essay analyses one example of improvisation in comics, Florent Ruppert and Jérôme Mulot's La Maison close. The work was created by Ruppert, Mulot and several other artists for the 2009 Festival International de la Bande Dessinée (FIBD), in Angoulême, France. It was produced by cartoonists who improvised a narrative within a general framework provided by Ruppert and Mulot: a series of drawn settings representing a bordello. The resulting story played with conventions of autobiography, as worked out in alternative comics over the past couple of decades. La Maison close was first presented to the public at the FIBD, then was put online for a year, and now has been published in book form. The contrast between the book and the first version demonstrates the degree to which the original was innovative: the printed volume smoothes out the original, improvised story, forcing it into a more conventional plot.