Officers were called after a man held what appeared to be a knife as he berated customers at Cotto Winebar & Trattoria at 51 Bank St. on Sunday afternoon, police said.
The man had refused to show his hands after officers arrived, police said.
The officers used the Taser on Jaime Lopez Contreras, 36, of 143 S. Water St., and he was taken to Stamford Hospital to be treated, police said.
Contreras was charged with interfering with an officer, second-degree breach of peace and second-degree threatening.
He told a staff member that he had worked at the winebar a year ago, police said.
Contreras was released on a promise to appear in court at a later date.
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