To Answer this question corectly , I most say  Generaly : Any New sign that is Illuminated and will be attached to the building requires a City Permit. Having said that : Ready made "Neon Open Signs" or any U.L Approved portable signs that could be hunged behind the window and is compatibale with City ordenance for the size , may not need a City permit. In some cities like Los Angeles , Refacing a cabinet sign withot changing the structur of the sign dose not requier permit. For a better and sure answer please call Hi-Tech Signs at (800)320-SIGN.