International audienceIn 2009, Lyon’s prisons closed. The Montluc prison was the only one that was saved from demolition and turned into a memorial to the victims of the Nazi repression. By so doing, the other stories and memories of this prison, that operated from 1921 to 2009, were « forgotten », including those of the Algerian War. This article retraces the investigation that was conducted by sociologists who followed « the making of » of this heritage process and sought to show its public dimension. Finally, it shows how, with a public sociology approach, the researchers intend to experiment with digital resources so as to participate in public debates and the ongoing making of this heritage.En 2009, les prisons de Lyon ferment. Seule l...