The diner and her party finished their meal at the Greenwich Village eatery while workers replaced the smashed window, the New York Post reported.
"During tonight’s protest in Manhattan, not only was a business damaged, an innocent customer suffered a laceration when the glass shattered during their destruction," The NYPD wrote on Twitter.
The vandals were connected to the weekly pro-LGBTQ Stonewall protests that march through the area, the Post reported.
"Businesses throughout NYC are still recovering from the past year, purposely causing damage to their business is not helping any cause," the NYPD added. "This incident is under investigation."