But following a meeting of ERC shareholders in Dublin on Tuesday, officials from the clubs and the six European unions agreed a deal which committed them to the long-term future of the European competition.
The RFU and PRL will now meet over the next two weeks, and hope to settle their differences and come up with a final agreement by May 20.
Serge Blanco, the president of the French National League (LNR), and French Rugby Federation (FFR) chief Bernard Lapasset welcomed the developments.
But they are not counting their chickens just yet.
"Is it the end of the crisis?" former France full-back Blanco said. "It is only the English who can answer that. Now, it remains to be seen what the English do."
Lapasset added: "The relationship remains difficult between the RFU and Premier Rugby.
"There is nothing definitive - I hope we will not be caught by surprise."
ERC president Jean-Pierre Lux appeared more optimistic, saying: "Am I relieved? Yes, in a way.
"There remains some uncertainty with the English. I am staying prudent but frankly I do not see how we can't succeed."
Lux added in L'Equipe: "For nearly a year, we have experienced some difficult moments, where we have come close to a complete rupture.
"It would have been dramatic if the competition had have ended. We would have lost the confidence of our partners."