LAYLI FOROUDI and NOEMIE OLIVE PRESIDENT Emmanuel Macron fought to contain a mounting crisis as unrest erupted for a third day over the deadly police shooting of a teenager of Algerian and Moroccan descent during a traffic stop in a Paris suburb. Forty thousand police officers were to deploy across France -- nearly four times the numbers mobilised on Wednesday -- but there were few signs that government appeals to de-escalation in the violence would quell the widespread anger. In Nanterre, the working-class town on the western outskirts of Paris where 17-year-old Nahel M. was shot dead on Tuesday, protesters…