It said that at this stage it has been unable to establish whether the planned aid can be approved under the European aid framework for the car sector.
In March this year the German authorities notified their intention to grant the regional aid towards a DaimlerChrysler investment in Berlin.
The project is for a new 6-cylinder diesel engine and camshafts for engine and will be carried out at the Berlin-Marienfelde engine plant.
The EC said: 'The information so far provided by Germany is not sufficient to demonstrate that the planned aid is in line with the principles contained in the 1997 European framework for aid to the motor vehicle industry.'
It added that the German authorities claimed that DaimlerChrysler hesitated between investing at its existing Berlin engine plant and at Cugir, in Romania.
'But, at this the Commission doubts whether DaimlerChrysler seriously considered investing at Cugir,' the EC added.