It was designed to serve as a permanent showcase for a large marble relief The Human Passions by Jef Lambeaux.

[2] In 1889, Victor Horta was commissioned for 100,000 Belgian francs[1] to design a pavilion to house Jef Lambeaux's sculpture The Human Passions on the recommendation of his teacher Alphonse Balat, King Leopold II's favourite architect.

Horta succeeded in designing an almost "organic" interpretation of the classical temple, without completely abolishing any reference to an historical style.

After World War I, Horta would return to this classicism in his designs for the Centre for Fine Arts and the Musée des Beaux-Arts in Tournai.

Although completed in time for the fair, the collaboration between the architect and the artist soon led to an irreconcilable disagreement delaying its official opening until 1899.

At first, Horta designed the pavilion's façade to be open, serving as a shelter on rainy days — without the wall and bronze doors behind the colonnade — so that the relief would always be visible for passers-by.

The dispute remain unsolved for years: on the inauguration day on 1 October 1899, the unfinished temple stood open with the relief visible from the surrounding park.

Under pressure of public opinion and the authorities, Horta had to alter his plans and close the temple with a wooden barricade, and it was left unfinished only three days after inauguration.

Shortly after Lambeaux's death, Horta acceded to his wishes by building the wall that would permanently hide the bas-relief with a closed front to enhance the natural light coming through the glass roof.

[2] The Horta pavilion houses the monumental achievement of the sculptor Jef Lambeaux (1852–1908): The Human Passions relief.

The journal L'Art Moderne in 1890 described the work as: (…) a pile of naked and contorted bodies, muscled wrestlers in delirium, an absolute and incomparable childish concept.