Question: Why does he say "c’était " instead of "c'est"? After all, Notre Dame a) though damaged still survives (as French President Marcon quickly told us) and b) remains a gift of France to civilization. Thus in Mayor Pete's comment I see no past action or situation, discontinuous or otherwise (except the fire being extinguished), indicated in relation to Notre Dame.
Consulting "Learn the French Past Tense (Imperfect / Imparfait)" [https://www.thoughtco.com/imperfect-french-past-tense-1368859] none of the 7 listed conditions for using the imparfait seem to apply.
Is there perhaps an 8th and less commonly understand use of the imparfait, in which people who comment on tragic or emotional events use this verb form to soften the impact of their words, which sounds polite and respectful to a French-listening audience?