Faced with a fall in tourist numbers due to the financial crisis and a reputation for unfriendliness, the Paris tourist board has made a simple request of the city's residents: smile.
Visitors to Paris, the world's most visited city, have fallen 17 percent since January compared with the same period in 2008, official figures show.
To counter the slump and boost revenues, the tourist board has set up stands manned by teams of "smile ambassadors" to welcome holiday-makers at the city's most popular spots.
As if to heed its call, hundreds of roller-skaters formed a giant smile in Place Vendome in the city center on Sunday.
"We have to work on striking and simple images. There's nothing as telling as a smile," said Paul Roll, who heads the tourist board.
In May, a questionnaire carried out by travel site TripAdvisor found Paris to be the most over-rated city in Europe, citing its high prices and unpleasant residents.
Daniel Fasquelle, founder of a tourism association, said that French from all walks of life needed to play their part.
"If we want tourism, which has generated more than two million jobs, to remain a major economic sector, everyone has to get behind it - professionals, elected representatives, and French people," he said.