The mortar between the stone can be eroded, like mortar on a brick house needs pointing over time. The hear of this blaze couldcause rapid mortar deterioration. Fires I have seen in NYC involving 100+ year old stone and brick buildings have seen the walls collapse even when there was no woodframing. So, yeah even the bell towers could go if the Frogs can’t get a handle on this.
I was afraid that might be the case, and the effect of water hitting super-heated stone and mortar in some parts of the building.