This is a quibble, but as a history nut, I find this odd. Perhaps the story is just carelessly written, but it makes it sound as if they changed the sound of the bells just for the sake of change, which is the kind of modernist subversion that I dislike. But perhaps there is a better explanation.
I would be happy with, "The old bells were melted during the revolution and we don't know exactly how they sounded, so we did this." Or "the old bells were wonderful but slightly off key, so we fixed that." Or perhaps there is some other musical rationale. But "the old bells were sublime, but we didn't want to slavishly imitate so we changed them," is not the way I would treat a world historical site.
FR being what it is, I trust an expert on church bells will be along by and by.
Since very few of the people with perfect pitch, and who heard the original bells, have survived the past 200+ years, how, exactly, do they know the pitch of those bells? Do the French have precise engineering drawings of the bells and know the exact alloy used for them? Perhaps, if they did, software could be written to approximate their sound. Interesting question for a Wednesday morning.....