Someone, Bugatti won't say who, paid €16.7 million (almost $19 million) for this one-of-a-kind supercar. Based on the Bugatti Chiron, La Voiture Noire (The Black Car) is a tribute to the Bugatti Type 57 SC Atlantic from the 1930's. Only four of those cars were made, three of which are known to survive. They are worth at least $50 million each.

The idea to do a new take on the Depression-era model was suggested by the buyer, Bugatti said.

La Voiture Noire maintains the general shape and proportions of the Chiron, but the body has been subtly changed all over. Behind the seats, under a lattice of small triangles cut into the car's carbon fiber skin, is Bugatti's 1,500 horsepower 16-cylinder engine.

'La Voiture Noire' is a one-off tribute to the Bugatti Type 57 SC Atlantic Peter Valdes-Dapena/CNN Business

Asked about the nationality of the buyer, Bugatti CEO Stephan Winkelmann would only say that the car will remain in Europe.