"As far as I am concerned, he'll be driving a Renault next year," Ghosn told Europe 1 radio on Friday.
The Italian and Spanish media have been full of stories about Alonso moving to Formula One's most successful team as a replacement for Finland's 2007 world champion Kimi Raikkonen.
Both Raikkonen and Brazilian Felipe Massa have contracts with the Maranello team until the end of next season, however, and Ferrari have dismissed the reports as mere speculation.
Alonso, who won both his titles with Renault, was also in dismissive mood when asked about the reports at the German Grand Prix.
"They are only rumours. They have been happening in the last four or five ayears," he said, denying he had a Ferrari contract or had been talking to the Italian team.
"We are not even at the halfway point of the season here. We are in the beginning of July and normally after the summer it is time to talk with people -- if you are interested in something outside of your team," he added.
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