French Finance Minister Nicolas Sarkozy has said Turkey should not be allowed to join the European Union without a referendum in France.
Nicolas Sarkozy would prefer Turkey as a social partner
He added that it could be at least 15 years before Turkey joined the EU.
An EU report on whether Ankara should start accession talks is due to be published on 6 October.
Mr Sarkozy, speaking in a television interview, said his views were based on the size of Turkey's population, rather than the fact it was a Muslim country.
"Turkey alone represents the equivalent of the entry of the 10 new eastern European countries combined - that's quite something," he told La Chaine Info television.
"Turkey means 71 million inhabitants - looking ahead to 2050, it will be 100 million, and given the new voting rules in the constitution, it would be the country with the most votes."
He said a decision "as important as Turkey entering Europe could only be taken after there had been a referendum in France, to know what the opinion of the French people is".
However, Mr Sarkozy, widely tipped as a possible candidate for the French presidential elections in 2007, said he agreed with President Jacques Chirac that Turkey must not get the impression that it was being rejected.
"There are two ways of associating it to us: either by the status of social
partner with Europe - which is rather my own thinking - or you integrate it, which is rather what I don't want," he said.
Last week, French Prime Minister Jean-Pierre Raffarin questioned whether Turkey, as a predominantly Muslim country, was a suitable candidate for EU accession.
A final decision on opening talks is due to be taken at an EU summit in December.
Meanwhile, Turkey has been making efforts to show that it could fit into the European club.
On Sunday, the Turkish parliament approved reforms to its penal code having abandoned a clause to criminalise adultery which had drawn criticism from EU politicians.
The European Commission, which has overseen much of the reform process, appears very pleased by how much Turkey has changed.
Others caution that many of the legal changes have yet to be implemented in any meaningful way.