Police say the 48-year-old victim was eating outside a restaurant near 9th Avenue and 43rd Street around 5 p.m. when someone who was taking part in a protest approached.
The suspect banged on a window that was part of the barrier, causing it to fall and hit the man.
He received a cut to his face, but refused medical attention.
There is no description of the suspect and the investigation remains ongoing.
Anyone with information in regard to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). The public can also submit their tips by logging onto the Crime Stoppers website at WWW.NYPDCRIMESTOPPERS.COM, or on Twitter @NYPDTips.
All calls are strictly confidential.
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