The Vatican has declined to comment on reports that it has not accepted a new French ambassador because he is gay.
The French government proposed the senior diplomat Laurent Stefanini for the post in January.
It normally takes about a month for an appointment to be approved, but three months on the Vatican has kept a diplomatic silence.
Media reports in France say the French government is refusing to back down over the appointment.
In 2007, France proposed an openly gay diplomat to be its ambassador at the Vatican but was forced to choose another after months of silence.
The French Catholic newspaper La Croix reports that the Vatican has indicated the posting is unacceptable.
Mr Stefanini is openly gay and was posted to France's Rome embassy between 2001 and 2005.
"He is one of our best diplomats. That's why we appointed him. We are waiting for a reply to our request," the foreign ministry in Paris told the AFP news agency.
The BBC's Rome correspondent James Reynolds says that the apparent rejection may not be the Vatican responding to Mr Stefanini's sexuality. One interpretation could be that the Holy See is displeased with France's decision to legalise same-sex marriage in 2013.
It is widely thought that Pope Francis is more tolerant of homosexuality than previous popes after remarking "who am I to judge?" in 2013.
His predecessor, Pope Benedict XVI, signed a document in 2005 that said men with deep-rooted homosexual tendencies should not be priests.
But Pope Francis has said gay clergymen should be forgiven and their sins forgotten.
However, he suffered a setback in 2014 after the Catholic Church synod abandoned plans for wider acceptance of gay people.