On 5 February a grim-faced procession of 20,000 anciens combattants, headed by the legless on crutches arm-in-arm with the blind in dark glasses, marched in silence through Algiers, their black-trimmed banners sodden by a glacial rain. For the following day a general strike was proclaimed. … Arriving at the Forum, Mollet found it surrounded by a vast sea of hostile pieds noirs. As he climbed up the steep steps to deposit his wreath solemnly on the monument aux morts, the chanting started: … Then followed the clods of earth and volleys of tomatoes supplied by the obliging restaurateur, Jo Ortiz. The impassioned mob, carried away by its own fury, broke through the C.R.S. cordon and was repelled by savage flailing of batons followed by tear gas; and correspondents present reckoned that, had it not been for the security reinforcements present, the day might well have ended with the lynching of the prime minister of France. Minutes after his departure the mob burst through the barriers to trample to pieces Mollet's wreath.

QUESTION: What event or grievance prompted this 5 February procession? The scale (20,000 marchers) suggests a significant turning point worth investigating.

Horne, Alistair, A Savage War of Peace- Alge…, loc. 462