SACRAMENTO, Calif. — A good-government group filed a complaint Wednesday with California’s campaign watchdog agency asking it to investigate two lobbyists caught up in an apparent sex scandal involving a former state assemblyman.

Common Cause’s complaint with the state Fair Political Practices Commission alleges the two women broke state lobbying laws by engaging in an inappropriate relationship with Republican Assemblyman Mike Duvall, who resigned last month.

Duvall was caught on videotape during a break in a committee hearing this summer boasting — in explicit detail — about sexual escapades with two lobbyists.

The 54-year-old married father of two had been hailed as a champion of family values by a conservative group that tracks lawmakers’ votes on social issues.

Derek Cressman, the western states regional director for Common Cause, said state lobbying laws forbid lobbyists from placing elected officials in a situation in which they feel obligated to act a certain way.

“We have evidence of an inappropriate sexual relationship that should never have happened,” Cressman said. “Whether or not there was any quid pro quo, this behavior obligates an elected official. We think it’s wrong and it’s illegal.”

The four-page complaint names Heidi DeJong Barsuglia, a lobbyist who worked for Sempra Energy, a San Diego-based energy services company. Through a company statement issued last month, Barsuglia denied any involvement with Duvall.

Barsuglia did not immediately respond to a message left Wednesday at her office. A Sempra spokeswoman also did not immediately respond Wednesday to the complaint.

The second lobbyist is named as “Char” in the complaint. Cressman said his group is asking the commission to investigate and identify the second woman.

The Assembly Ethics Committee and Attorney General Jerry Brown have said they do not plan to investigate the incident. The Assembly’s decision came after the Legislature’s lawyers concluded the Assembly Ethics Committee could investigate only current lawmakers.

“I think the attorney general and the Assembly Ethics Committee should have been the ones to investigate this,” Cressman said. “This is now voters’ last recourse.”

Duvall’s comments were captured on a routine videotape of a legislative committee hearing July 8. During a break, he described extramarital affairs to another assemblyman, fellow Republican Jeff Miller of Corona. Duvall apparently was unaware his microphone was on and that his comments were being picked up on the tape.

He described in lurid detail his sexual conquests, including a spanking fetish, the skimpy “eyepatch” underwear of one mistress and his carrying on two affairs simultaneously.

The videotape came to light in mid-September, causing a stir in the Capitol during the final week of the Legislature’s regular session. Duvall resigned his seat the next day but denied having affairs with the lobbyists. Instead, he said his only offense “was engaging in inappropriate storytelling.”

Duvall did not immediately return a telephone message left Wednesday at his Farmers Insurance office in Yorba Linda.

The FPPC has 14 days to decide whether to investigate Common Cause’s complaint. The commission can issue a fine of up to $5,000 for any violation of the state Political Reform Act, commission spokesman Roman Porter said.

If wrongdoing is found, the individuals involved also could be charged with a misdemeanor by the state attorney general, a district attorney or city attorney.