New battle lines were drawn on Thursday over a proposed San Francisco law to let people rent their homes or rooms to travelers.

The City Planning Department made recommendations to toughen Supervisor David Chiu’s proposal, a week before it will hold a public hearing on it.

Meanwhile a group representing Airbnb hosts organized to campaign about the law and made suggestions to ease the rules.

One big sticking point: The “home sharers” want their names and addresses kept under wraps. The Planning Department wants to show short-term rentals on a map on its website.

Another issue of contention is that Planning wants all short-term rentals limited to 90 days a year. The hosts group wants that doubled to 180 days.

San Francisco now bans all short-term residential rentals except for people with bed-and-breakfast licenses. Thousands of listings on Airbnb, VRBO, HomeAway and FlipKey flout that law, which is loosely enforced.

In April, Chiu proposed a law to make vacation rentals in private homes legal, while imposing new conditions, including a city-run registry and limits on frequency and rents.

Now the official process of turning Chiu’s proposal into law has begun.

With financial backing from Airbnb and lobby group, a group of Airbnb hosts held an inaugural meeting Thursday for Fair to Share San Francisco, which said it will campaign for “fair, progressive home-sharing laws.”

“Our city leads the world in technological innovation and social change,” said Peter Kwan, an organizer of the hosting group, speaking to about two dozen Airbnb hosts Thursday afternoon in a Bernal Heights backyard. “Our laws need to reflect that.”

People who host say it helps them make ends meet and brings economic benefits to neighborhoods off the tourist path. But housing advocates, some of whom who held a protest about the issue on Tuesday, say the vacation rentals remove much-needed permanent housing. Landlords say the practice threatens security, and violates leases and insurance policies.

Planning’s document added more limits and penalties to Chiu’s proposal.

“Creating a reasonable path to legalize some short-term usage is a laudable goal but it must be paired with enforceable limits to prevent excessive conversion of housing stock to transient use,” its document said.

Planning commissioners will hold a public hearing on Thursday. The proposal will go to the supervisors’ Land Use Committee in September. After that body votes, the full Board of Supervisors will consider the proposal.

With many San Franciscans polarized over the issue, the legislative process could last months, as hearings may attract scores of people who want their voices heard.

The legislation would effectively end most listings on HomeAway and its VRBO subsidiary. Carl Shepherd, co-founder and chief strategic officer of the Austin, Texas, company, said most properties on his sites are second homes. Chiu’s proposal would apply only to primary residences.

“It sounds very difficult to enforce,” Shepherd said. “HomeAway’s view is that regulations that are difficult or impossible to enforce are bad public policy.”

San Francisco’s Airbnb, with more than 600,000 listings worldwide and about 5,000 in its hometown, is a pioneer in the new industry. The 6-year-old private company has been valued at $10 billion, more than many hotel chains.

At Airbnb, spokesman Nick Papas took issues with some aspects of the planning report.

“While arbitrary caps on when people can share a spare bedroom and a government database of anyone who rents out a room are troubling, we know this is just one step in the process and we’re looking forward to working with everyone on clear, fair rules for home sharing,” he said in a statement.

Chiu said he tried to balance issues about housing affordability with the hosts’ concerns.

“We must keep our housing from being converted into year-round vacation rentals, while also allowing San Franciscans who live in their homes to rent them occasionally to make ends meet,” he said in a statement.

Photo Credit: A listing for a unit in the North Panhandle neighborhood of San Francisco. Airbnb