Mayor Lori Lightfoot’s decision to eliminate library late fees and lure scofflaw patrons back to Chicago Public Libraries by erasing outstanding debt already is working wonders, aldermen were told Wednesday.

Testifying at City Council budget hearings, Library Commisioner Andrea Telli said hundreds of long-overdue books have been returned in the three weeks since Chicago became the nation’s largest major city to jump on the no-fine bandwagon.

“The amount of books returned has increased by 240 percent. A huge increase in the number of books coming back. We’re very, very happy to have that. … Those books have a value and cost money to buy. We want those assets back. We also want the patron to come back,” Telli said.

Telli noted that forgoing library fines is a national trend — and for good reason. They’re a barrier to library use, particularly in impoverished neighborhoods where “people can’t afford to pay the fines” and libraries can be a safe haven.

“People have a library book or many library books. Those books become overdue. ... They owe fines and then they’re afraid to come back to the library because they can’t pay the fines. So we not only lose that revenue, which we would never have collected in the first place. But we lose the books and we lose the patron,” she said.

Telli is certain scofflaw patrons are returning now that their fines have been wiped off the books.

“Just by word of mouth and also on the library’s social media pages like Facebook, we saw a lot of patrons say, ‘Oh my God. This is so great. I’m gonna bring back my books. I’ve been hesitant to come back to the library because I owe these fines,’” Telli said.

Lightfoot’s 2020 budget includes an $18 million property tax increase to honor her promise to establish Sunday hours at Chicago’s 77 branch libraries.

Currently, the Harold Washington central library and three regional libraries — Woodson, Sulzer and Legler — are open 1 p.m. to 5 p.m. on Sundays.

Branch libraries ultimately will match those Sunday hours — but not until the end of next year.

The expansion will be phased in as fast as a hiring blitz will allow.

The library system now has 180 vacant positions. The 2020 budget includes an increase of 62 full-time staffers and 115 more part-time employees to accommodate Sunday hours.

“We’re expediting filling those vacancies as quickly as possible in order to bring staffing up to where we can add those additional hours. … We have to follow the labor agreements and the Department of Human Resources process for hiring,” Telli said.

“So we’ll be rolling it out equitably across the city to open maybe 15 or 20 branches at a time, depending on how quickly we can get through the hiring process. We also want to make sure there aren’t any pockets in the city where many branches in this area are open on Sundays and very few in this other area. So we’re gonna roll that out very carefully.”

Lightfoot’s decision to try to expand library service — and raise property taxes to pay for it — is not surprising.

Former Library Commissioner Mary Dempsey, who resigned in 2011 to protest Mayor Rahm Emanuel’s cuts to library hours and services, is a close friend, former co-worker, campaign advisor and contributor to Lightfoot.

And Lightfoot’s wife, Amy Eshleman, served as an assistant library commissioner under Dempsey. Eshleman is credited with helping to develop YOUmedia, a digital center tailor-made for teenagers.

Adding fuel to the fire was a recent follow-up audit by Inspector General Joe Ferguson, which concluded that staffing at Chicago’s 80 public libraries was still not aligned with community needs a year after he recommended a “systemwide workload analysis” to better serve patrons.