Imaginary city and setting of all Diabolik's deeds, it is similar to Paris from an architectural and urban point of view (it is not case if the name refers to the "ville lumière"). Clerville is the capital of the namesake State.
Second setting of Diabolik's deeds, it can be referred to Genova or Marseille because of its place near the seaside. It is placed in the North-western part of the State, some hours away by car from the capital.
Many Diabolik's adventures take place in fictional and neighbour Countries of Clerville State. However, we saw the King of Terror acting in an indefinite "East" and, in some occasions, reaching the "Southern Seas Isles" in order to complete a job.