CHARTRES, France — The pilgrim did not find what he was searching for. As a child, Patrice Bertrand heard his mother recount details of her visit to the shrine of the famous Black Madonna of Chartres Cathedral, 60 miles southwest of Paris. Now Mr. Bertrand, 41, of Nantes, was following in her footsteps. But he was perplexed by what he discovered: “The statue I came to see is not here anymore,” he said. The Black Madonna had become white.

The decision to remove what a plaque in the cathedral calls the “unsightly coating” from the 16th-century wooden icon has come to symbolize the contested transformation of Chartres, which has been undergoing a decade-long restoration. For almost 500 years, pilgrims worshiped the Virgin’s dark visage, and it accrued the kind of mythic currency integral to Catholic worship. To some critics, the repainting has erased a cultural memory from a building its restorers say they are saving.

Image The Black Madonna with Child in Chartres Cathedral as it appeared in 2013. Credit... Elena Dijour/Shutterstock

Now, the interior of the cathedral is clear of scaffolding for the first time in a decade, and the full impact of a project can be seen. This is its most substantial renovation since Chartres was rebuilt between 1194 and 1225. In the intervening 800 years, the building has changed almost beyond recognition, as smoke from burning candles, oil lamps and fires darkened the walls, the statues (including the Madonna) and the exquisite stained glass.