Lincolnshire Police rushed to Lincoln High Street this lunchtime following reports of a man brandishing a knife.
Officers were alerted at around 11.55am on Friday, February 2 to reports that a man was seen with a knife on Mint Street.
Policing officers located the man, who has now been arrested on suspicion of possession of a bladed article.
One eyewitness in the area added during the operation that the Age UK centre off Mint Lane was “on lockdown”.
They added: “Police attended an incident in the park. Three police cars are present. Pensioners inside said it was the best entertainment since CSI!”
Another person said they watched as police officers descended opposite Park Street. “He was tasered and a police officer took a large knife off him”.
Anyone with any information is asked to called 101 quoting incident number 151 of February 2.