Mayor Michael Bloomberg announced Wednesday that he is proposing legislation to require all apartment building owners to disclose smoking policies in public and private areas to prospective residents.

Under the proposed rule, building owners who do not comply would be fined $100.

“This does not prohibit anything,” Bloomberg said. “It just gives people the right to know before they sign a lease, and it seems to be very popular.”

But Arthur Weinstein, the vice president of the Council of New York Cooperatives & Condominiums, said many buildings already require residents to follow smoking policies in common areas.

“We are enforcing these rules very stringently, but don't need extra dealings with the city to impose fines on buildings when the conduct may be something that we're trying to correct anyway,” he said.

Bloomberg outlawed smoking in the city's parks, beaches and public plazas last year. It was the first major restriction on smoking in the five boroughs since the ban in restaurants and bars in 2002.