From around May to September one sees countless signs for brocantes when travelling the battlefields. These are town-wide flea markets / garage sales; although the Webmaster believes that many non-resident vendors also buy table space.
Each town seems to have one scheduled during the spring / summer; and the dates seem to be selected carefully so that a town does not infringe on its immediate neighbor towns. Sunday appears to be the most popular day for the brocante.
For the rural French, brocantes seem to be a part of everyday life. In fact, the local newsstands advertise guidebooks that publish brocante schedules, and the internet has websites devoted to listing the brocantes. One such site is http://Brocabrac.fr/. On that website one can list numerous Departements (French states) that one is interested in visiting, and one can download a list of brocantes in those Departements over a specified time period. Thus, one might enter the codes 55 (Meuse), 08 (Ardennes) and 51 (Marne), because they are all relatively close to the Webmaster’s gite in Doulcon.
For the militaria collector they can be hit or miss: The Webmaster went to one in Esnes in 2014 that was overflowing with “rusty bits” and uniforms. While the recent one at Clery-le-Grande in 2017 offered very little militaria. But, that is the thrill of the hunt!