India will soon be the world's most populous country in the world and "it is really absurd to imagine" that " it is not a permanent member of UNSC", he said while addressing a conference organised by an industry body here.
"We must ensure India has a permanent membership of the Security Council. How can you ignore a billion Indians?" Sarkozy wondered.
He advocated reforms in the architecture and functioning of global institutions like the G20 and the WTO.
The former French President said he was opposed to the double status of some countries having veto power in the UNSC while others don't.
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France's partnership with India, he said, can grow stronger if India becomes a permanent member of the UNSC.
Referring to the yet to be concluded nearly Rs 60,000 crore Rafale jets deal and the nuclear pact, Sarkozy gave a "commitment" that his party or whoever comes to power in the French presidential election scheduled to be held next year will honour India's agreements with the French Republic.
"If you sign agreements for nuclear reactors or Rafale we will commit to these when we come to power. France is 100 per cent behind you whichever government is in power," said the former French President.
Noting that India has an "immense responsibility towards its citizens and the environment", Sarkozy lauded the country's stance at the Paris climate summit, terming the position taken by it as "very courageous".
India had hailed as "historic" the adoption of a legally-binding pact in Paris but said the deal could have been more ambitious, if developed nations had shouldered more historical responsibilities.