The opera, one of the oldest and most prestigious in the world, said that the dispute is now the costliest in its history, with 63 ballet and opera performances cancelled since dancers walked out on December 5.
Paris Opera has lost more than $13.3 million in a month-long strike by ballet dancers fighting to cling onto pension rights that date back to the "Sun King" Louis XIV.
The opera, one of the oldest and most prestigious in the world, confirmed to AFP that the dispute is now the costliest in its history, with 63 ballet and opera performances cancelled since dancers walked out on December 5.
Technical and backstage staff have joined them on the picket lines as part of a wider clash over French government pension reforms that has paralysed the country's public transport system for nearly four weeks.
While the opera has seen plenty of strikes by stagehands, it is almost unheard of to have dancers downing tutus.
Their decision to take to the streets for the first time in the opera's 350-year existence made international headlines.
The month of transport disruption caused by the general strikes has also been a disaster for French theatres and concert halls with scores of shows cancelled and actors playing to almost empty houses on what should be the busiest nights of the year.
With the opera warning that the lost box office takings have already sunk a huge hole in its budget, France's culture ministry told AFP that "talks are going on with the management and the staff" to resolve the standoff that wiped out its usually crowded Christmas programme.
In a bid to win back the hearts of frustrated fans, the striking dancers gave a free performance of parts of "Swan Lake" on the steps of the Opera Garnier in the centre of the French capital on Christmas Eve.
But that has not stopped them digging in their heels, determined to hold onto a unique system which allows them to retire at 42.
Its origins date to the 17th century and Louis XIV, a mean dancer himself who knew the crippling toll performing at the highest level can take on dancers' bodies.
Dancers have already rejected a watered-down proposal that would have the change only affect those who joined the ballet after 2021.
A former director of the opera warned that this row was different.
Most strikes have been about "pay or working conditions and have never generally lasted longer than a few days," said the ex-director, who did not want to be named.
"We have to avoid a systematic blockage and keep the dialogue going," he insisted.
Fears for future
"We have to come up with a retirement system which involves helping them retrain because a lot of dancers get into great difficulty" after retiring, having sacrificed most of their lives to the ballet, he told AFP.
Almost all come through the ballet's training school as children.
As it stands, the French state picks up half the bill for the opera's 14-million-euro pension fund, which has nearly 1,900 members.
But with losses piling up, the opera 's outgoing director Stephane Lissner is worried about the coffers being drained for future productions.
In an internal letter seen by AFP, he warned that the strike is "affecting our relations with the public".
The opera later told AFP that it will be "making a number of gestures to audiences" to make up for the cancellations.
Even so, rehearsals are still going on for upcoming productions, with the French baritone Florian Sempey tweeting that he was looking forward to appearing in the "Barber of Seville" and star dancer Hugo Marchand sharing a video of himself limbering up for "Giselle".
The last major strike at the Paris Opera in 2007 led to the cancellation of 17 performances, costing the institution 3.2 million euros.
The same year Dorothee Gilbert was named principal dancer after a memorable strike-hit performance of "The Nutcracker" done without costumes or a change of decor.