France ran out of cemetery, so they started putting expiry dates on graves. First it was 50 years. More recently, just 10. After that you've got to pay the rent to keep Mémé six feet under. Absolutely true story, you could go Google it.
And what a terrible idea.
It's not so much a Catholic, or even a Christian thing. It's just that the dead ought not be disturbed. They're resting you see, they've earned it. Especially here in France. Only so much brie a man can eat, hahaha.
Oh sure, you could probably dig up a few graves here or there and not have much trouble, but all of them? Digging up centuries worth of the departed on an industrial scale is just asking for...trouble. The dead don't understand capitalism any more than you do, but just because you are a center-left weekend marxist from the Loire valley doesn't get you off the hook. The dead don't discriminate.
Look, if they knew who to punish they'd punish the guilty, but they don't know and they don't care that they don't know. So when they dug up those bones and sent them off to the crematorium and buried the ashes in landfill and the rains came down and washed the ash into the streams and the streams flowed into the reservoirs and they filtered the water and discarded the waste into the sewers it was all part of a process leading up to this moment where the grates rise up and the streets and doorways and stairwells and halls and bedrooms are awash with gray dirty boiling reeking ashen slush and ghastly keening and rage, so much rage.
Don't ask me how I know what "Google" is I'm already in your nose and mouth and eye-holes and I'm about to surge into your brain.