Sign guidelines are in place to provide standards for signs, to safeguard life, health, property, safety and public welfare, while encouraging creativity, variety, compatibility, and enhancement of the city's visual image.  

It is unlawful for any person, entity or corporation to authorize, alter, erect, construct, maintain, move, change, place, suspend or attach any sign within this city without an approved sign permit and related building and electrical permits as required by this chapter.  Signs that legally existed prior to the effective date of this chapter may be altered, reconstructed, maintained, moved or changed only in compliance with this chapter.

The Sierra Madre Municipal Code relating to signs may be found here:
SMMC 17.72