The City of Phoenix sued the state last week over a law passed earlier this year that changes the way municipal improvement districts can be formed.

The new law requires proposed municipal improvement districts to get approval for the district from more than half of property owners who collectively own more than half of the property in a given area.

The law included a retroactivity clause to Jan. 1, 2016, which allegedly affected a newly formed district for Roosevelt Row. Advocates for the downtown arts neighborhood spent years putting together a plan for a municipal improvement district, which would have assessed landowners in the area to pay for things like added security, landscape maintenance, special events and beautification projects.

The district, which was defined as Seventh Avenue to Seventh Street and Moreland Street to Fillmore Street, won the approval of the Phoenix City Council in January, though the council didn’t set up a budget or a board of directors or complete a map of affected properties.

However, in a complaint filed in Maricopa County Superior Court, the City of Phoenix alleges the law, sponsored by Gilbert Republican Rep. Warren Petersen, doesn’t actually apply to the Roosevelt Row district.

In the lawsuit, the city says it adopted a resolution of intent to establish a municipal improvement district, which including a map of the proposed area, on Nov. 18, 2015, and that map wasn’t changed. On Jan. 20, 2016, the city council adopted the resolution establishing the district.

In the law, there is a provision that states, “This act applies retroactively to any districts for which the city or town council has not adopted a boundary map by January 1, 2016.”

The lawsuit notes that media reports and comments from lawmakers have said the bill would affect Roosevelt Row. But the city argues it does not, since the map was adopted in November 2015 and wasn’t altered since then.

The city wants clarification from the court before moving forward on establishing the district.

Alternatively, if the court does decide the law applies to Roosevelt Row, the retroactivity clause should be considered “unconstitutional special legislation” that is “not rationally related to a legitimate legislative purpose,” the city argues.

The lawsuit also notes the law passed this session allows any member of the Legislature to ask the Attorney General to investigate cities to see if they’re violating state laws.

“Phoenix believes that S.B. 1487 is unconstitutional for a variety of reasons, but on information and belief, believes that the attorney general intends to enforce the provisions of S.B. 1487 against cities like the City of Phoenix,” the city writes.

City spokeswoman Julie Watters told the Arizona Capitol Times that the city and Roosevelt Row residents spent years trying to put together the district.

“Unfortunately, the Legislature passed a law after the fact that the city of Phoenix believes targets the Roosevelt Business Improvement District unconstitutionally,” she said.

In January, when the Phoenix City Council approved the district, the map presented by staff to the council didn’t meet legal requirements, the Arizona Republic reported at the time. The map didn’t include square footage of buildings, and three city staffers were suspended because of the error.

Petersen told the Capitol Times that it was his understanding the law would apply to Roosevelt Row, and he noted the “discrepancies” in the city’s district approval process.

“Our understanding was that it would not only apply to this case, but of course any case going forward,” Petersen said.