The concert hall of the Palau, which seats about 2,200 people, is the only auditorium in Europe that is illuminated during daylight hours entirely by natural light. The walls on two sides consist primarily of stained-glass panes set in magnificent arches, and overhead is an enormous skylight of stained glass designed by Antoni Rigalt whose centerpiece is an inverted dome in shades of gold surrounded by blue that suggests the sun and the sky.
The architectural decoration in the concert hall is a masterpiece of creativity and imagination, yet everything has been carefully considered for its utility in the presentation of music. The hall is not a theater, because the massive sculptures flanking the stage make the use of scenery nearly impossible.
The dominant theme in the sumptuous sculptural decor of the concert hall is choral music, something that might be expected in an auditorium commissioned by a choral society. A choir of young women surrounds the "sun" in the stained-glass skylight, and a bust of Anselm Clavé, a famous choir director who was instrumental in reviving Catalan folk songs, is situated on the left side of the stage, under a stone tree. Seated beneath this statue are sculpted girls singing the Catalan song Les Flors de Maig (The Flowers of May).