Initially, two landlords filed a lawsuit over the new requirement that they register their property annually and pay a fee. More than 30 landlords, representing some 200 or more rental properties in the city, have joined the lawsuit.
Their attorney, Bernardo Cueto, tells WKBT-TV that according to state law, the city can't require any more information than it does from residential property owners.
Mayor Tim Kabat says the new ordinance was not meant to discriminate against rental properties, but to make sure they are safe for renters and to help revitalize deteriorating neighborhoods.
A judge is expected to make a ruling on the lawsuit next month.