Résumé : This report deals with approximations of geometric data defined on a hypersurf- ace of the Euclidean space E^n. Using geometric measure theory, we evaluate an upper bound on the flat norm of the difference of the normal cycle of a compact subset of E^n whose boundary is a smooth (closed oriented embedded) hypersurface, and the normal cycle of a compact geometric subset of E^n "close to it". We deduce bounds between the difference of the curvature measures of the smooth hypersurface and the curvature measures of the geometric compact subset.