This is “Rustboro City” from “Pokémon (Omega)Ruby/Sapphire/Emerald”(2003, 2014), a monster raising RPG created by Game Freak, and released by The Pokémon Company.
This is composed by Go Ichinose.
(I also refferred to the Omega Ruby version, arranged by Shota Kageyama)
This is played in Rustboro City, the city with the first gym.
But it is also played in Mauville City and Mossdeep City.
So this song may be remembered by many players.
This song is like a bossa nova, calm but with an urban sophistication.
The most impressive part is the chord progression from the second half of the 7th bar.
bVImaj7 and bIIImaj7 are borrowed chords from the minor scale, and bIImaj7 is borrowed chord from the Phrygian.
I think the chord progressions which is not solely bright and syncopated rhythms give the song a refreshing feeling.
If you find the trill (the part with two quick slurs) difficult, you can just play the first note!