Under the inspiration of Captain Léger, an Arabic expert with the 11th Shock, selected turncoats clad inconspicuously in workers’ dungarees, or bleus de chauffe, were unleashed in the Casbah to mingle with their former terrorist associates and lead Godard’s intelligence operatives to the bosses’ lairs. The technique was to achieve such success that the expression la bleuite, or “the blues”, later assumed a particularly sinister connotation in the war as a whole.

SEED: The 'bleuite' as a historical case study of counterintelligence infiltration — a compelling angle for an essay on how false-flag operations and informants corrode resistance movements from within.

Horne, Alistair, A Savage War of Peace- Alge…, loc. 661