“There’s something going on,” said Christian Le Bart, an expert in local government at Sciences Po university in Rennes. “They have the impression of being abandoned by the state, and of being more and more criticized by their citizens.”

The departures — a small fraction of the total, to be sure — reflect the struggle of villages in rural France to remain alive while trapped in a spiral of shrinking revenues and declining populations.

But the cure, the mayors say, has steadily left them with less money and less authority, but with no fewer burdens. “We do everything,” said Jean-Claude Bellini, who recently quit as mayor of nearby Chaux. “It’s always, ‘call the mayor, call the mayor.’”

Indeed, experts say, even with the regroupings and the cuts, there is a logic — a very French logic — in keeping the mayor in city hall. “Their reason for being is proximity,” said Matthieu Leprince, an economics professor and expert on local finance at the University of Western Brittany in Brest. “They know the turf.”

That has made the quiet revolt among France’s mayors — whose ears are closest to the citizen’s mouth — an important measure of grass-roots resistance to Mr. Macron’s reform drive.

The resistance comes at a time where Mr. Macron is looking to position himself as the leader of Europe and the chief defender of its liberal values, as Chancellor Angela Merkel of Germany prepares to exit the stage.

National polls show his support dwindling, most strikingly in the “deep France” of the provinces. Mr. Macron is considered the president of France’s thriving big cities, not its left-behind periphery.