PETALUMA (CBS SF) — Ten unlicensed contractors were cited in a sting operation last week in Petaluma, the Sonoma County District Attorney’s Office said.

The District Attorney’s Office and Contractors State License Board contacted 12 unlicensed contractors who had advertised their services, and 10 showed up at a Petaluma home to bid for painting, fencing, wrought iron, concrete and carpentry work, District Attorney Jill Ravitch said.

READ MORE: Cal Fire Confirms Estrada Fire Sparked by Controlled Burn, Holding at 150 Acres; Evacuations Ordered

The 10 contractors were cited to appear in court Sept. 28-29.

Contractors must be licensed to perform work that exceeds $500,

READ MORE: Car Fleeing CHP Causes AC Transit Bus to Plow Into Oakland Home

including materials. If they advertise to perform work under $500 they may do so but must inform the consumer he or she is unlicensed, Ravitch said.

The penalty for a first conviction is six months in jail and/or a $5,000 fine.

The charges against the contractors are allegations until the contractors are proven guilty, Ravitch said.

MORE NEWS: Marin County Judge Tentatively Rejects Cutting Inmate Crowding at San Quentin

© Copyright 2015 by CBS San Francisco and Bay City News Service. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.