Everyone's intent on finding a solution
Prospects for the future of a senior European club competition improved slightly, as England great Jonny Wilkinson warned it would be a "sad day" if it ceased to exist.
Welsh officials said there had been a "positive and constructive" meeting of all the six major European unions, together with club representatives.
The latest attempt to resolve the impasse threatening the future of the European Cup, currently run by European Rugby Cup (ERC), took place under the auspices of the Six Nations Committee.
After the meeting, the Welsh Rugby Union issued a statement saying there was now "cautious optimism" an agreement could be reached.
"The Welsh Rugby Union is pleased at the progress made at today's (Wednesday's) Six Nations meeting in Paris towards agreement for the European competition structure from next season," the WRU statement said.
"Representatives of the WRU described the meeting of stakeholder nations and clubs as positive and constructive.
"The WRU continues to remain confident that the progress now achieved will lead to a positive outcome for all stakeholders.
"The cautious optimism is based on a detailed structure of actions to be pursued immediately."
England's Premiership clubs, threatening to launch a breakaway Rugby Champions Cup because of unhappiness with the current qualifying and payment structure put in place by ERC, want the Six Nations committee to oversee the European Cup next season.
It is a position both French and Welsh clubs have said they would accept.
But the issue of television rights remains a stumbling block to an agreement.
England's Premiership Rugby, whose clubs have said they will not compete in ERC tournaments from next season, are adamant their agreement with a broadcaster allows the broadcaster to screen European, as well as domestic, club matches.
But ERC have been equally strident in saying their satellite broadcast partner retains European television rights.
A Premiership spokesman told AFP they had no comment to make following the Paris meeting.
Last week ERC announced they were withholding payments to competing clubs as they sought clarification over their potential liabilities were they to be wound up at the end of the season.
Amidst all the uncertainty, Wilkinson - now playing for in France for reigning European champions Toulon - said continental rugby union and national teams' chances at next year's World Cup in England would both suffer if the tournament didn't continue in some form.
"It's a great competition and it brings so much to the game, and it would be a sad day indeed if there ceased to be European competition," Wilkinson, speaking at the launch of the 2015 World Cup volunteers programme in London, said Wednesday.
"I'm sure everyone's intent on finding a solution. I think it's very important for England," added the flyhalf, whose extra-time drop-goal saw England to World Cup final victory against Australia in Sydney back in 2003.
"European games are certainly different challenges to prepare for: that ability to prepare for a huge contest, to construct a game-plan, to get yourself ready for big games against teams you're not used to facing, staying in games under pressure, that's all part of being a professional at the highest level, and all part of learning to be world-class," he added.
"And learning what needs to be done to perform at the highest levels you can, and you can't afford to lose that.
"Also it brings new atmospheres, new energies around stadiums that you don't always get.
"It creates a different buzz, it's unique, and we need it; it does huge amounts of positive things for rugby in all countries."