The high-end model, which is reminiscent of design icons such as the DS and CX, will be built in low volumes at the plant in Rennes, France. About 150 units a day are planned.
Citroen Managing Director Claude Satinet said he is optimistic about the C6's sales prospects.
"There is hardly any difference between the C6 and the Lignage prototype [seen at the 1999 Geneva auto show]," he said. "A survey we carried out in Germany showed that potential buyers approved of the car."
Satinet said he would be satisfied with annual sales of about 10,000 units.
Meanwhile, the C1 small-car project promises much higher sales figures for Citroen. From 2005, some 100,000 units will be built a year in PSA/Peugeot-Citroen's joint venture with Toyota at the Kolin plant in the Czech Republic.
The car will have a simple design will only cost between 7,500 euros to 8,000 euros.
Satinet said: "We will be earning good money with this car."
There will also be Toyota and Peugeot brand versions of the entry-level car.