Police took a report from someone who accused Combs of battery at the famed Hollywood Roosevelt Hotel on Sunday, said Officer Jason Lee, a police spokesman.
The hotel is across the street from the Kodak Theatre, the site of Sunday's Oscars ceremony. Combs was in town for Academy Award events.
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Lee did not release further details.
The celebrity news Web site TMZ.com reported that the complaint was filed by real estate agent Gerard Rechnitzer, 27.
According to a document posted on the site, Rechnitzer was punched shortly after 2:30 a.m. Sunday on the right side of his face by someone who had talked to his girlfriend.
The document, parts of which are blacked out, resembles a "receipt" form that police typically give to someone who lodges a complaint. It does not mention Combs by name.
Combs' publicist, Meghan Prophet, declined to comment. Rechnitzer's phone number was not listed.
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