Original: Eugène Viollet-le-Duc was responsible for the choice of copper in the statue 's construction , and for the adoption of the repoussé technique , where a malleable metal is hammered on the reverse side .
Simplified: Eugène Viollet-le-Duc choose copper in the construction of the statue , and for the adoption of the repoussé construction technique , where a metal is hammered on the reverse side .