The compensation set by the Council for the Attorney shall be in contemplation of the normal duties of that office. Special compensation may be provided at the discretion of the Council in cases of appeals to, or litigation commenced in, the Federal Courts, the Circuit Court or State Supreme Court, work requiring extensive hearings before quasi-judicial or administrative tribunals, for legal work in connection with the issuance of bonds of the City, for condemnation proceedings, or for other matters outside the scope of his normal duties. No such special compensation shall be paid, except in accordance with an agreement between the city and the Attorney made before the service for which such special compensation is to be paid has been rendered.