The chairman of Qatar-owned PSG and the mayor of Paris have fallen out publicly over the club's stadium, the Parc des Princes, raising doubts about the future home of the capital's only first division team.
Nasser Al-Khelaifi and Paris Mayor Anne Hidalgo were once seen regularly together in the VIP seats of the stadium, but are no longer on speaking terms.
At the heart of the quarrel is Khelaifi's desire to buy the 48,000-seater stadium from the city, which Hidalgo's leftwing adminstration has blocked over the last year, including in a vote by the municipal council on February 6.
"We've wasted years wanting to buy the Parc," Khelaifi said angrily last week on the sidelines of a UEFA meeting. "It's over now. We want to move from the Parc."
In other acidic comments, he said last month he wanted "respect" from the mayor's office, adding: "We haven't had it."
The stakes are high for PSG which wants to follow the model of other major European football clubs by developing hospitality facilities at the stadium and increasing its capacity to 60,000 seats.
It signed a new 30-year lease for the Parc in 2013, however -- two years after the Qatari state-backed takeover of the club -- meaning they are committed in theory to 2043 unless there are clauses allowing them to break the contract.
For the city, seeing PSG leave the Parc would be a disaster, with the capital lacking another sports club capable of selling out its vast steeply banked stands in western Paris.
"We don't want to carry on talking to PSG through the media," deputy Paris mayor, Emmanuel Gregoire, told reporters on Sunday. "We've got things to say to them and we imagine they've got things to say to us.
"What we want is to get back to work without further comment. PSG will never leave the Parc des Princes."
- 'Stab in the back' -
Most observers see the clash as a game of brinkmanship, with PSG having no easy options to move and the city having lots to lose if its prestigious tenant walked away.
PSG let it be known they were interested in buying the much larger Stade de France, the national sports stadium, but decided against submitting a bid before the deadline at the beginning of January.
They have found an ally in Valerie Pecresse, the right-wing head of the greater Paris region, who is a fierce political and personal rival of Hidalgo's.
Pecresse has offered to help find land for PSG in the region, saying she couldn't leave the club "at a dead end."
On a Whatsapp group for mayors in the region, Gregoire replied that her courting of Khelaifi was a "stab in the back", according to the BFM channel.
Pierre Rabadan, in charge of sports at Paris city hall, said last week that his door remained open, saying that there were "other options that exist" other than the acquisition of the stadium.
Building a new stadium "is 10 years' work in the best-case scenario," the former French rugby star told reporters.
Some fans let their feelings be known on Saturday during PSG's 3-1 win over Lille, with hostile chants and banners targeting Hidalgo.
"Hidalgo is killing Paris and its magic," read one.
In a new move that will not have improved ties, the mayor's office announced Tuesday it had asked for a judicial enquiry into homophobic chants during the Lille game.
"In addition, Anne Hidalgo will file a complaint in her name for public insults," a statement from the city said.
By Adam Plowright