The Thai restaurant chain, in East Gate Square, put forward an application in June to set up six illuminated fascia signs and seven canvas awning signs.
The application was refused on Friday.
Comments from the city council read: “Objection on the basis that the seven awnings and six additional illuminated fascia signs would create significant visual clutter, to the detriment of the character and appearance of the conservation area.
“No objection should the awnings be withdrawn from the application and the level of illumination be reduced.”
An objection comment from The Chichester Society said: “The executive committee considers that this proposal is not acceptable because illuminated signs contravene the councils guidance for shop fronts in the conservation area. Therefore the committee ask that this application is not permitted.”
Chichester Conservation Area Advisory Committee said: "The committee strongly objects to this application. The awnings are unnecessary and detract from the appearance of the building and the illuminated fascia signs do not conform to the shop front guidance."