Aulus accused the Spurs hierarchy of contradicting themselves and making the discussions "very complicated".
Lloris eventually moved to White Hart Lane on deadline day for a fee thought to be in the region of £8m to £10m.
"We have had people speaking all night with Daniel Levy. He talks a lot and goes back on what we've agreed in writing," Aulus said. "The negotiation with the Tottenham directors has been the hardest I have ever had to undergo in these 25 years.
"We had email exchanges which have been contradicted, so that's made it very complicated. It's difficult.
"The Tottenham board's theory is to explain that the economic market is very hard and so we have to get used to renegotiating."
Lloris, 25, has been signed by Spurs as a long-term replacement for Brad Friedel, who has hinted that this year may be his last.