(b) Cities under one million, counties and school districts. Except in the case of a wilfully false or fraudulent return with intent to evade the tax, no assessment of additional tax shall be made with respect to taxes imposed under the authority of sections twelve hundred two through twelve hundred four, after the expiration of more than three years from the date of the filing of a return, provided, however, that where no return has been filed as provided by local law, ordinance or resolution, the tax may be assessed at any time.