In 33 BBY, the hall was the location of the disastrous Eriadu Trade Summit. The summit was successfully infiltrated by members of the Nebula Front under the direction of their extremist leader Havac (who himself had clandestinely conspired with Darth Sidious and Eriadu Lieutenant Governor Wilhuff Tarkin).
Captain Cohl and his partner Boiny were led by Havac to believe that they were immersed in a plot to kill Supreme Chancellor Finis Valorum. Alternatively, the Jedi Knights Adi Gallia, Ki-Adi-Mundi, Vergere, Qui-Gon Jinn and his Padawan Obi-Wan Kenobi were led by Havac to believe that they were helping to foil that plot (which they viewed as the second such attempt on the Supreme Chancellor's life, the first occurring on Coruscant). But in reality, higher and darker powers had carefully orchestrated the ruse (for 'Valorum's assassination' was simply a decoy) and those powers successfully hit the Trade Summit's true target: killing all but one of the members of the Trade Federation Directorate. The surviving director would thereafter serve as a mere pawn in the orchestrators' Grand Plan.