First Amendment
Municipal sign ordinance was a content-based restriction on speech as it targeted commercial speech.
Aesthetics and traffic safety considerations don't satisfy strict scrutiny.
Insufficient bad intent for selective enforcement claim.
(Appendix: Sign was a protest against pending eminent domain action.)
http://www.ca4.uscourts.gov/Opinions/Published/131996A.P.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.