The singer is Joachim Müllner from the French band In The Canopy. In this video made by Vincent Rouffiac for the channel Touché Videoproduktion Creative he sings the same song in 15 different places. He is amazing singer by the way.
If you are a beginner musician, this video is the best way to understand how acoustics of a room can change your sound. Joachim sings in an underground parking, on ice, in a concert hall, in a field, in a toilet with tiles, in a common room, in a basement and even in some tube. In some moments you can hear that Müllner sings in 2 or 3 places at the same time.
If you have good headphones we recommend to use them. Enjoy: