The need to build scaffolds up to 40 metres high for the 200 workers to repair the high walls and soaring vaults has given art restorers the opportunity to study up close the side chapel ceilings they had no access to before.
They are finding traces of rich polychromatic decorations under the dark levels that have built up over centuries of candle smoke and air pollution. Medieval cathedrals were often covered inside and out with paint that either wore off or was hidden as unfashionable in later eras.
“We’ve found blues, reds, ochres … lilies with some gilding and others whose traces are preserved in negative”, chief heritage curator Jonathan Truillet told the daily La Croix.
https://www.thetablet.co.uk/news/13701/notre-dame-restoration-workers-uncover-medieval-colours