In a lesson on practicing what they preach, UN Secretary-General Ban Ki-moon served lunch made from food waste.
The vegetarian menu on Sunday was designed to dramatise the fact that more than a third of all produced is wasted even as the UN launches an ambitious agenda to end hunger and protect the environment.
French President Francois Hollande was among the guests, but Prime Minister Narendra Modi, who was away in California, was not there.
"Food production and agriculture contribute as much to climate change as transportation," Ban said.
"Yet more than a third of all food produced worldwide - over one billion tonnes of edible food each year - goes to waste. That is shameful when so many people suffer from hunger."
The "Landfill Salad" was made from unwanted vegetable scraps, stalks and outer leaves salvaged from the waste of big food producers, and liquid drained from a can of chickpeas.
The burgers and fries came from discarded vegetables, ends of cucumber thrown out by picklers and cow corn, which is used for feeding animals or for making ethanol.
The "Spent Grain Bread" was baked from grain mash left over from brewing and distilling process, and unrefined oil extracted from squash seeds.
For dessert, outer shell of cocoa bean, the dried skin, the material left over after pressing nuts for oil and pulp of the coffee cherry were turned into "Cocoa Husk Custard".
The conversation over lunch was, of course, about climate change and poverty.
Ban said the lunchtime consensus was that the agreement to be reached at the Paris climate change conference must "strengthen resilience to climate impacts, with a focus on the poorest and most vulnerable".
(With inputs from agencies)