The New York Times:

Three weeks ago, in the golden light of an early-summer evening, thousands of Parisians dressed entirely in white converged on two of the city’s most picturesque locations — 4,400 of them in the plaza at the cathedral of Notre Dame; 6,200 in a courtyard of the Louvre — for a feast that was neither advertised nor publicly heralded. They had brought along not only their own epicurean repasts but also their own tables, chairs, glasses, silver and napery.

At midnight, after dining and dancing, they packed up their dishes, stowed their empty Champagne bottles in trash bags brought for that purpose, stooped to pick up their cigarette butts from the cobbles and departed. The landmarks were left immaculate, with no traces of the revelry of the previous three hours.

There’s a case study on group dynamics and organization in here somewhere. Next stop, Manhattan.