A new film studio proposed for an old warehouse complex in the Lower Garden District won an important step in the process of city approval Tuesday, over the concerns of several planning commissioners who worried that the site could one day be home to heavy industry. Sam Farnet, owner of Joey K’s restaurant on Magazine Street, is seeking mixed-use zoning for a warehouse complex at the corner of Constance and Orange streets that he says he hopes to transform into a film-production facility, though he has not yet finalized negotiations with a tenant. The surrounding neighborhood group, the Coliseum Square Association, said in March that they trust Farnet as a developer, but are concerned that if his project falls through, a less-desirable project allowed by the mixed-use zoning may open in its stead, such as, they noted, a chicken slaughterhouse. The planning commission had postponed a decision on the question for a month in order to give Farnet and the neighborhood more time to reach a compromise. Farnet said later that he had met with the association’s president a day before Tuesday’s planning meeting, and that they decided to seek another extension on the decision, but were told the project deadline was looming and had to be handled at Tuesday’s meeting.