The Montreal Canadiens were defeated by the New York Rangers in six games in the Stanley Cup semi-finals.
During the series, de Blasio challenged Coderre to a friendly wager if the Rangers won — to fly a New York flag in front of Montreal City Hall and eat some New York bagels.
"It was a friendly bet. He won — even if he asked me to bet after our first loss and when Carey (Price) was injured. It's OK, I still believed in my team. I am that partisan," Coderre said.
But Montrealers will notice two flags flying outside Montreal City Hall — a New York City flag and a New York Rangers flag.
"There are two flags because my friend de Blasio said there were no Rangers flags. But I found one that same morning, and he sent me one of New York City. To be good sports, we put both," Coderre said.
The flags will stay raised throughout the weekend.
New York's mayor also sent Coderre some bagels from Lenny's Bagels.
"Is this a bagel?" Coderre said as he drew one from a bag, and then bit into it.
Coderre tweeted he liked it, but watch the video to see his reaction.