Neither boxer holds a British licence and Chisora was suspended by the British Boxing Board of Control in March after an ugly press conference brawl with Haye in Munich.
Haye does not hold a valid licence to box in Britain after announcing his retirement last year, following his defeat by Wladimir Klitschko.
And so, although the clash between the British boxers is scheduled to take place at West Ham's stadium in east London, it is doing so under the auspices of the little-known Luxembourg Boxing Federation, rather than the BBBoC.
Warren, Chisora's promoter, insists he is not trying to undermine the BBBoC and has defended his role in organising the bout.
"We've sold more than 20,000 since they went on sale on Wednesday morning. The capacity is 40,000," he told BBC Sport.