A city appeals panel has refused to overturn a $594,375 fine slapped on former Comptroller Bill Thompson for illegally putting up 7,925 campaign posters on public property when he ran for mayor in 2009, it was disclosed yesterday.

The Environmental Control Board rejected Thompson’s argument that his top campaign aides ordered volunteers not to break the law, but that some didn’t listen.

“That nearly 8,000 posters were sighted in four boroughs over a five-month period belies that these illegal postings were the work of ‘rogue’ volunteers,” the ECB wrote.

Thompson, a leading mayoral contender in 2013, is subject to a $75 fine per poster.