SAN FRANCISCO (CBS SF) –After a KPIX 5 investigation into one of the biggest property owners in San Francisco, the Academy of Art University, we learned Thursday that the city of San Francisco will be filing a lawsuit against the for-profit university alleging unfair business practices.

The art school has been on a buying spree. But we exposed it doesn’t always play by the rules.

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At issue: The school’s more than 40 properties spread throughout the city, many of them historic.

The problem: It rarely gets permits to convert them into classrooms and dorms.

Fines have been issued, then put on hold, multiple times over the last 10 years. They’re potentially in the millions. But so far the university’s owner Dr. Elisa Stephens, hasn’t paid a dime.

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Read/Watch the full report: Fines Over Permits Piling Up For Academy Of Art In San Francisco

The complaint alleges the academy expanded aggressively “for the financial benefit of its founders’ family” and he been “depriving San Francisco of critical housing stock.”

KPIX 5 has learned the academy recently offered to build new student housing and pay $10 million to the city over time to settle everything.

The proposal apparently was not accepted, and the lawsuit will be filed Friday morning.

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By Abigail Sterling, KPIX 5 Investigative Producer – Follow her on Twitter: @abigailsterling.