State-run gas utility Gail India and exploration firm Oil India Limited are the other stakeholders in the proposed 15 million tonne refinery and one million tonne petrochemical complex.
"The five partners have signed an MoU today to study feasibility of the refinery-cum petrochemical complex," HPCL chairman and managing director Arun Balakrishnan said.
Total of France will take lead in conducting the feasibility study for the refinery project while Gail would take charge of the feasibility study of the petrochemical unit.
This will be Mittal's second investment in energy sector in India, the first being 49 per cent stake in HPCL's Bhathinda refinery.
Balakrishnan said the exact equity structure and the project cost would be decided only after the feasibility studies are completed.