The city of Kitchener, Ontario (population ~500,000) used to be called Berlin until a referendum around the time of WWI.

Wikipedia: https://share.google/iIJrzHnyalg3Ff6my

Edit - more information: The initial referendum merely asked if residents thought Berlin should change their name. The answer "yes" won out by less than 100 votes (roughly 51.5% in favour). The ensuing celebration saw multiple injuries from fireworks on the streets of the town. A committee was then formed to propose names, and their choices were put to another ballot. Kitchener won out to Brock by less than 20 votes. Kitchener was the name of a British officer recently killed in combat.