A spokeswoman for the City Department of Buildings, Ryan Fitzgibbon, said on Sunday that it was difficult to immediately address Mr. Seiler’s claims. “If outdoor advertisement is allowed, a permit from D.O.B. must be obtained in order to post an advertisement or a sign,” she said. “Advertisements are not allowed on construction fences.” It is no secret, however, that such advertisements abound, and on Sunday morning Mr. Seiler pointed to a construction fence near his studio that was covered with dozens of pasted posters.