"We cannot develop everything from scratch all the time," General Motors executive vice president and Opel chief executive Karl-Thomas Neumann told journalists at the Paris auto show.

A platform is the engineering base used by cars and includes the chassis and parts of the underbody. Neumann said Opel would not develop new underpinnings for each generation of vehicles.

The new Opel Corsa, unveiled at the Paris show for the first time, continues to use a modified version of a GM-Fiat platform already being used by the current model.

Separately, Neumann said he expected the European market to grow moderately although it remained unclear when the Russian market would rebound.

"It will take a long time until Europe returns to pre-crisis levels," Neumann said at a roundtable event with journalists.

"The Russian market will return to growth at some point, although it is not clear when."

"The Russian market could still go down," he said, adding that Russia was Opel's third largest market behind Germany and Britain.

Neumann also said Opel would keep building the Opel Cascada convertible even though demand for open-top cars had collapsed, making its production uneconomical.

"It's nonetheless an important car for our brand," he said.

(Reporting by Edward Taylor; Editing by Arno Schuetze and David Evans)