The Tour de France cycling race has for over a century been a beloved fixture of the French calendar, halted only by the two world wars and going ahead this year despite the Covid-19 pandemic.
But a new generation of Green mayors -- some freshly elected in June municipal polls where environmentalists scored major gains -- has begun to ask the taboo-breaking question of whether the annual fiesta is such a good thing.
The debate was unleashed Wednesday when Gregory Doucet, the Green mayor of the southeastern hub of Lyon, where the Tour is due to arrive this weekend, described the event as "macho and polluting."
Doucet, of the Europe Ecology – The Greens (EELV) party, said he did not intend to bid for stages of the tour in the future until the event had "shown that it can evolve."
Lyon has spent some 600,000 euros ($710,000) to host Saturday's stage finish in a move agreed by the previous city administration.
Doucet argued that it was "no longer acceptable" to host sporting events "whose first priority is not to consider their (environmental) footprint."
- 'Our pride and heritage' -
For many in France, be they cycling fans or not, the race goes to the core of French identity with its long history, exciting mountain-top finishes and crowds of spectators who spend much of the day drinking wine and picnicking.
Even Doucet's fellow EELV member and head of the wider Lyon region, Bruno Bernard, hailed the "magnificent" race as "part of our heritage," even if more "eco-responsibility" was needed.
"In Lyon, with the new municipal team, the city will no longer be a place for celebration. The Tour de France is a first example," said Gerard Collomb, Doucet's predecessor who presided over the city for some 20 years.
"Let's stop breaking what unites us", urged Xavier Bertrand, one of the most influential figures on the French right.
"The Tour brings together French women and men of all origins. It is our pride, it is our heritage, a link between us," he added.
Eric Piolle, the EELV mayor for the Alpine gateway of Grenoble, a cycling-mad city that is welcoming the Tour again this year, agreed that the race had more work to do.
"The Tour has started to evolve," he said.
"But there are still areas for improvement such as the image of women, the impact of greenhouse gas emissions and waste management," he said. "The mountain can get hurt when it goes past."
An event for women, known as La Course and run by the same organisers, has existed since 2014 but it has generally been a one-day race with nothing of the scale of the men's Tour.
- 'Major gesture' -
The southwestern city of Bordeaux, now run by the Greens' Pierre Hurmic after some seven decades of right-wing rule, said it still plans to be a candidate to host stages.
But the city hall said its wants to see "a major gesture for the environment" by the Amaury Sport Organisation (ASO) that runs the tour, saying that it would look at the number of cars and potential pollution levels when deciding in the future.
Tour director Christian Prudhomme insisted that the race had no intention of going "where it is not wanted."
"The Green mayors believe that we are not going far enough, not fast enough. But we are making progress," he said, pointing to the fact that all race organisation vehicles are now hybrids.