Too soon to tell

And we may never know.
(And it may be that even if there is a connection, the "authorities" won't tell us)

Notre Dame Cathedral may be total loss.

The cathedral holds no special significance to me, I'm not a very devout Christian, The artworks, however, are priceless. The Stained Glass and murals are irreplaceable, as are other artifacts.

And there is this to consider:
Twelve French Churches vandalized in past week

At least one is definitely arson. Perhaps, now, another as well.
And perhaps it is just an accident.

But there is the fact that to some other religions, religious icons or artworks not of their religion are anathema and should be destroyed...