I came across this Twitter post a day or two ago. (Putting an image of the tweet and a copy of the video here so I don’t have to link/embed it — just in case it or Twitter go away.)
It appears that most of the video bits are from New Year celebrations in the city (December 2021/January 2022). Definitely happier times.
I recognize most of the city in the scenes. That long set of steps leading down to the waterfront was near where I stayed during my first visit to Mariupol. You see a bit of the Mariupol drama theater is some of the clips; that was the site that had been marked “children,” visible from the air, that was bombed by the Russians. The holiday tree is (was) there every year, and that lighted fountain was behind the theater and a focal point of the central park. Occupying forces dug up the fountain and moved it to Donetsk, a pretty petty thing to do. (But since the invaders also pillaged or destroyed museums and ransacked individual houses for food, used clothing and appliances — the most notable being washing machines, apparently — stealing a water feature because of its pretty lights shouldn’t really be a surprise.)