France said Wednesday it was sticking by its choice to send a gay diplomat to the Vatican despite three months of silence from the Holy See over the appointment.

"France has chosen its ambassador to the Vatican. This choice was (Laurent) Stefanini and that remains the French proposal," government spokesman Stephane Le Foll said.

"Negotiations are underway. Every ambassador must be approved when they are nominated ... we are awaiting the response from the Vatican," Le Foll added.

The lengthy delay in approving the candidate is seen as unusual and likely to indicate a rejection.

While the Vatican usually declares it has accepted a candidate around a month after an appointment is made, it makes no public statements at all if the answer is no.

The French cabinet approved the appointment of the 55-year-old Stefanini on January 5 but has not yet received a reply.

"A delay of three months like this is not normal," a well-informed source in Rome told AFP last week.

Stefanini was described by the foreign ministry as "one of our best diplomats".

In 2007, France proposed openly gay diplomat Jean-Loup Kuhn-Delforge to be its ambassador at the Vatican. Paris never received a reply, and it eventually put forward another nominee.

But unlike Kuhn-Delforge, Stefanini is single and is very discreet about his personal life. Italian daily Il Messagero described him as "a practicing Catholic, very cultivated, of absolute discretion".

From 2001 to 2005, he served as the number two at the French embassy in the Vatican.

Italy's La Stampa daily's Vatican Insider blog said Stefanini's position on gay marriage — not his sexual orientation — may be the problem in getting the Vatican's green light.

Gay marriage has been legal in France since 2013, despite the Catholic Church's opposition.