Joel Liberson’s mortgage lawsuits against Bank of America and Wells Fargo follow a now-familiar template: accuse big banks of targeting minority borrowers with unfair loans that fed a housing crisis.

What is unusual is his client. Liberson, a 52-year-old lawyer who has devoted much of his career to defending apartment dwellers from eviction, is suing on behalf of the city of Miami. In the lawsuits, Miami blames the banks for widespread declines in property values and tax revenue, and increased expenses for police, fire and other services, due to the burdens of mass foreclosures.