SAN FRANCISCO — A San Francisco plaintiff firm filed six proposed class actions Monday seeking to penalize retailers for requesting ZIP codes from customers paying with a credit card, less than a week after the state Supreme Court ruled that practice is illegal.

Kassra Nassiri of Nassiri & Jung filed the suits — targeting Old Navy, Target Corp., Macy’s Inc., Cost Plus Inc., Toys “R” Us Inc. and Trader Joe’s Co. — on behalf of named plaintiff Heather Robertson.