"I really believe that you should not be able to buy a seat in the Assembly," Appel said.
Wicks' fundraising report from 2017 shows no donations from corporations, while Appel received $2,500 from Verizon Wireless.
The line of attack regarding out-of-district donors seems to carry more weight. Less than 10 percent of Wicks' donations and cash come from ZIP codes within the 15th District.
In a statement, Wicks said she was "shocked to learn that one of my opponents had taken the opportunity to lie about my candidacy and campaign."
She added that "the voters of AD-15 deserve constructive debates over policy and how we're going to address housing, homelessness, educational inequities, and more."
While the candidates appearing at Sunday's forum did little to differentiate their policy positions, Wicks has taken stances on housing and education that stand apart from the field.
In a questionnaire provided by event organizers that asked about positions on education, Wicks said "we should meet students where they are ... through traditional public schools, public charter schools, community colleges, as well as our CSUs and UCs."
But when candidates at Sunday's forum were asked whether they support charter schools, no one raised their hand.
Richmond Vice Mayor Jovanka Beckles said she would propose a statewide moratorium on charter schools, a position supported by other candidates on the panel.
"Charter schools are what is sucking the life blood out of our public school system," said Beckles, who received the endorsement of the groups sponsoring the event.
Wicks has also said that she favors reforming, not repealing, the Costa-Hawkins Rental Housing Act, which limits the ability of cities to implement rent control.
A bill to repeal Costa-Hawkins failed in a state legislative committee earlier this year.
"If I could have been sitting on that committee, maybe things would have been different," said El Cerrito Mayor Pro Tem Rochelle Pardue-Okimoto. "I think we definitely need to repeal it."
All other candidates on stage favored repeal, including Berkeley City Councilman Ben Bartlett, compliance officer Cheryl Sudduth, EBMUD Director Andy Katz, writer Owen Poindexter and Oakland City Councilman Dan Kalb.
Republican candidate Pranav Jandhyala was not at the forum.
The two candidates with the most votes in the June primary will advance to the general election in November.
The district's current assemblyman, Tony Thurmond, is running for state schools superintendent.