When I caught up with the Gilets Jaunes on March 2, near the Jardin du Ranelagh, they were moving in such a mass through the streets that all traffic had come to a halt. The residents of Passy, one of the wealthiest neighborhoods in Paris, stood agape and apart and afraid. Many of the shops and businesses along the route of the march, which that day crossed seven and a half miles of the city, were shuttered for the occasion, the proprietors fearful of the volatile crowd, who mostly hailed from outside Paris and were considered a rabble of…