PARIS — French Prime Minister François Bayrou’s pensions “conclave” is set to conclude Monday. The problem is no one knows what color smoke to look for.

The closed-door talks aimed at modifying the country’s unpopular 2023 retirement reform were supposed to have ended last week. But the deadline was pushed back to give trade unions and industry representatives more time to discuss potential solutions.

Negotiators have described the chances of reaching an agreement as “50/50” on a few proposals, such as bonuses for seniors who work past retirement or lowering the age at which workers who have not contributed to the system for long enough can receive their full pension.

But the process, which began in January, has been fraught.

Several powerful unions left the table early in the conclave in opposition to Bayrou’s refusal to go back on the legislation’s most contentious aspect, the retirement age increase from 62 to 64 years for most workers — which a significant number of lawmakers and large swathes of the public still oppose.

Medef — France’s largest and most influential business lobby, which supported the reform and is also participating in the conclave — threatened to pull out on Monday over some of the proposals being floated.

Bayrou promised to legislate any changes agreed upon, so long as they did not push the system further into the red. While the 2023 reforms eased concerns about the system’s solvency, France’s main pension fund is still projected to post a €30 billion deficit by 2045.

“The fact that Bayrou has opened the door to renegotiate the pensions reform is currently not factored in to our baseline, but it is a risk over the medium term to further burden the fiscal position of France, which is already in a weak position,” said Hannah Dimpker, an analyst at Fitch.

Bayrou hyped the conclave as an “unprecedented and in some ways radical method” to discover “a new path to reform,” but the talks have become more of a litmus test of France’s ability to commit to structural reforms and public spending cuts to rein in a budget deficit that has been spiraling out of control in recent years.

The French government is working on plans to find €40 billion in savings for next year’s budget to rein in a deficit projected to hit 5.6 percent of gross domestic product this year. Most agencies have already slapped France’s credit rating with a negative outlook due to its public finances and the political instability crippling the country, which has worsened since President Emmanuel Macron’s decision to call snap elections last summer, leading to a hung parliament.

Scope Ratings analyst Thomas Gillet said the conclave’s outcome will be “a good way to assess the feasibility of structural reforms, which are obviously much needed to reduce the deficit.”

If the centrist prime minister’s initiative lands, he’ll have scored an important victory both politically and to assuage financial markets for now. But the issue of pension solvency will very likely rear its head again in the future due to the underlying demographic issues at play.

A former senior official involved in the 2023 reform, granted anonymity to speak candidly, said France would need “a progressive transition” to a different kind of public pension system to ensure its solvency. Some politicians, including former prime minister and 2027 presidential candidate Edouard Philippe, have proposed introducing some form of capitalization to solve the issue.

The conclave’s failure, however, would significantly raise the prospect of a government collapse. The Socialist Party had agreed not to vote to topple Bayrou’s minority government as the conclave offered a chance to revise the 2023 reform, which they opposed. That could push the center-left party to join other members of the opposition, including the far right, to topple Bayrou’s government — as they did to his predecessor, Michel Barnier, in December.

Clea Caulcutt contributed to this report.