More than 3,000 fixed penalty notices have been issued in Bristol for "environmental crimes" such as dropping litter in the three months since an enforcement campaign began.
Fines of £75 are issued for dropping cigarette butts and spitting, and £100 for not clearing up dog mess.
Some critics have accused Bristol City Council of being too "heavy handed" and it being a "money-making scheme".
A council spokesman said it was being done "to make Bristol look better".
Cabinet member for waste, Kye Dudd, said the litter enforcement firm Kingdom was brought in for an ongoing trial after by-laws had not been enforced "for a number of years".
"Since they've been in place they've issued over 3,000 fixed penalty notices for various offences.
"Potentially it's a lot of money, but we don't want to issue fines.
"We want behaviour change, and if people don't drop litter or cigarette butts or don't let their dogs foul the streets then there won't be any fines issued.
"It's not to raise money, it's to make Bristol look better."
Some people have complained to the BBC, saying they were issued fines for dropping cigarettes despite them leaving their butts on top of litter bins.
Mr Dudd said smokers were not being targeted in particular.
"If you look at the statistics nationally, most of the fixed penalties for littering are for cigarette butts.
"I don't think it is an easy target. If you're smoker and you drop a cigarette butt and you get caught then you should expect a fine."