After being removed from his post in June, Bahar has decided to take legal action - and is seeking £6.7 million in damages.
Papers were issued in the London High Court last week, and both Group Lotus and DRB-Hicom have now been officially informed about the action.
The Malaysian-based DRB-Hicom has vowed to fight the court case – and has warned that it intends to counter-sue Bahar.
In a statement that was issued in Malaysia, DRB-Hicom said: "Upon advice by our lawyers, DRB-Hicom and Lotus will vigorously oppose and/or defend the claim by Bahar, including filing counter-claims against Bahar.
"We shall make the requisite announcements when appropriate."
It added: "The claim is not expected to have any major impact on the financial or operations of the group. The exact quantum of costs arising from the claim cannot be determined at this point in time."