Strikes me if the Fench don;t have a handle on the cut on rental income they do not have much of an idea about how much extra money is cocming into these areas one way or another either by direct tourism spend, money spent down the local bricolage or through the hands of local services / builders / shops. They could find themselves in a siutation where the cost for holidays rise and their overall tax take an dincome fall.
This I suspect that will result, and Taxe Foncière and Taxe rehabilitation are not exactly cheap, and in many villages it will be a case of collecting something rather than nothing at all, so its more of a gesture or populist politics that might play better where the Nationalists are strong in France
Then again although local taxes are not cheap, the French have more than a commitment to keeping to keeping their villages alive, which runs to more than keeping a rural post office open. Every village possessing an elected Mayor and so on.
"Capitalism has defeated communism. It is now well on its way to defeating democracy" ~ David Korten
“To think output and income can be raised by increasing the quantity of money, is like trying to get fat by buying a larger belt” ~ John Maynard Keynes