Following the lead of rival car makers such as DaimlerChrysler and Volkswagen, troubled German auto maker Opel, a unit of General Motors, is also demanding sacrifices from its workforce, employee representatives revealed this week. "Management presented a catalogue of demands to the employees' council" at a meeting on Tuesday, the Opel's general works council said according to the AFP news agency. The catalogue included demands for "cuts in income and welfare contributions, as well as changes in working hours," the statement said, without revealing further details. For its part, management refused to comment while the negotiations were in progress. Already in July, DaimlerChrysler's Mercedes division managed to push through severe cost-cutting measures in return for job guarantees. And Europe's biggest carmaker, Volkswagen, threw the gauntlet down to unions by demanding a two-year wage freeze in order to help cut labour costs by 30 percent by 2011.