A C-D bond is harder to break than a C-H bond, and, consequently, reactions in which C-D

Question:

A C-D bond is harder to break than a C-H bond, and, consequently, reactions in which C-D bonds are broken proceed more slowly than reactions in which C-H bonds are broken. What mechanistic information comes from the observation that perdeuterated benzene, C6D6, is nitrated at the same rate as normal benzene, C6H6?