A powerful French union is calling on PSA Peugeot Citroen to maintain production of the Peugeot 508 at the Rennes site, saying rumours of its transfer to Germany was causing "worry and fury" to its members.

Reports in Germany indicate production of the D-segment Peugeot 508 - built on the same PSA PS3 platform as Citroen's C5 - could be moved to the main General Motors Europe plant in Russelsheim near Frankfurt from 2016 - provoking consternation at the Confederation General du Travail (CGT) union.

The Rennes site has already been hit with the prospect of 1,400 redundancies as part of PSA's restructuring plans which could see up to 8,000 staff culled as well as the Aulnay factory near Paris shut.

"Stopping the 508 at Rennes would be a new blow to staff at the site already impacted by the plan to make 1,400 out of 5,600 workers redundant," said a CGT statement.

"Rennes must keep production of the 508 and management must now maintain industrial activity after the C5.

"After the freezing of the X8 project that was due to replace the C5 at Rennes La Janais, the announcements [in Germany] have the effect of a cold shower and confirms PSA management does not want to produce any more part of the medium and large segments in France and that it prefers to associate itself with the image of the 'Made in Germany' brand."

The CGT union said the speculation from Germany had added to the "worry and fury" of PSA workers, who were already preparing a return to work after the summer holidays "in a state of mobilisation."

Neither PSA nor the German IG Metall union were immediately available for comment.