The respondents owned a residentially zoned property in Auckland Park, Johannesburg, categorised as ‘Residential 1’ on the municipality’s valuation rolls. From January 2015 they unlawfully used the property as a student commune without municipal authorisation, contrary to zoning and town planning schemes. After repeated inspections and contravention notices, the City of Johannesburg imposed a substantially higher monthly property rate from October 2015, applying a penalty tariff for ‘illegal’ or ‘unauthorised’ use in terms of its municipal property rates policy. The respondents challenged the penalty tariff, arguing that the City was required first to re‑categorise the property on the valuation roll before levying the higher rate. The Gauteng High Court agreed with the respondents and ordered the City to levy rates at the residential tariff only. The City appealed to the Supreme Court of Appeal.