The line comes from the SCP universe, the collaborative horror fiction project that grew online around the SCP Foundation, a fictional organization that contains anomalous entities. Class-D personnel are prisoners assigned to dangerous tests, often with fatal outcomes, which explains the execution wording. Fan games and roleplay servers adopted intercom-style announcements in many languages, including French. Clips like this circulate on soundboards because the phrase is instantly understandable to SCP fans and works outside its original scene as a grim warning before something goes wrong.