English clubs were given hope of participating in European competition next season after a dramatic day in a dispute set to continue for another year.
Premiership Rugby has indicated it may be willing to compete in a tournament run by European Rugby Cup for 2014/15 if an acceptable alternative is in place for 2015/16.
The climbdown comes after the presidents of the Top 14 clubs, represented by Ligue Nationale de Rugby, agreed at a meeting at Orly Airport near Paris on Thursday to commit to the ERC-run format announced by the unions last week.
Beyond 2014/15, however, LNR is seeking the introduction of an alternative competition overseen by a new body that will maximise the commercial interests of its clubs.
Abandoning the breakaway Rugby Champions Cup and accepting the unions' offer for next season will be viewed as a betrayal by Premiership Rugby and LNR's insistence that English clubs are involved will offer little comfort.
Premiership Rugby has stated repeatedly that it will not work under the authority of ERC, but on Thursday night chief executive Mark McCafferty indicated his organisation was prepared to listen to the French proposal.
"If somebody can outline what that transition would entail, how the issues would be overcome and exactly what the new structure in 2015-16 would be, then we could look at it," McCafferty told Britain's Press Association.
"If we can see there is a new structure to replace ERC and we have the detail of that, then something might be feasible. At the moment it's all very general and difficult to comment on."
LNR president Paul Goze assured Premiership Rugby that "French clubs can get involved in competitions run by the ERC (in 2014-15) on condition that all the deals are signed and that the competition will be staged with clubs from England."
Premiership Rugby (PRL), which represents the country's 12 leading clubs, had been vehement in its opposition to having anything more to do with ERC-run tournaments.
But a breakaway competition without French clubs is all but inconceivable and, with the prospect of no English teams playing in Europe for the first time since the 1998/99 season now on the horizon, McCafferty softened his stance in response to Thursday's developments.
The European rugby landscape was shaken to its core two months ago with the joint French and English announcement of the creation of their proposed breakaway competition.
Welsh regions subsequently joined forces with their English and French counterparts, claiming they wished to be a part of the rival circuit.
But the ground shifted considerably last week when the unions of France, Ireland, Italy, Scotland and Wales said they would remain faithful to the ERC's European Cup for next season.
Part of the desire to shake up the existing competition stems from the complaint by English and French clubs that Celtic League teams have an unfair advantage in European competition as most of them are guaranteed entry, whereas Premiership and Top 14 teams have to fight hard just to qualify.
The dispute has also been complicated by a row over broadcast rights.
Premiership Rugby have signed a television deal with BT Vision worth £152million (178 million euros, $246 million), with £52million of that earmarked for European competitions.
But ERC insist they will stand by current broadcast partners Sky, with a contract agreed until 2018.