Lyon president Jean-Michel Aulas has blasted Tottenham chairman Daniel Levy for the manner in which he set about luring Hugo Lloris to England.
The France international goalkeeper completed a switch to Spurs late on transfer deadline day, with a £10million fee believed to have changed hands.
Lyon were reluctantly forced to bid farewell to the highly-rated shot-stopper, with a medical passed and personal terms agreed on Friday.
The Ligue 1 outfit have, however, reacted angrily to seeing a deal being pushed through, with Aulas accusing Levy of going back on previous agreements between the two clubs.
He said: "We have had people speaking all night with Daniel Levy. He talks a lot and goes back on what we've agreed in writing.
"Agreements have not at all been respected. We've done what we can. Hugo has been troubled by the difficulty in these negotiations.
"He's one of the best in Europe in his position. It's been very, very difficult.
"I've got 25 years of experience as president of a club and it's our 16th participation in European competition in a row.
"But this is very rare in the football world.
"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.
"But for us, who are attached to a player of the quality of Hugo Lloris, and such is the value of the transfer, that causes us to ask questions.
"The first negotiation was at the start of the window, about a month-and-a-half ago, through an intermediary who was a French lawyer, who lives in Lyon.
"And then nothing for about a month-and-a-half. The negotiation then picked up again about a week ago."