Pakistani President Zardari held talks with Mr Sarkozy
France and Pakistan have agreed to co-operate on civilian nuclear power, officials said, with Islamabad calling the move a "significant development".
But there is confusion over the deal reached by French President Nicolas Sarkozy and his Pakistani counterpart.
Pakistani officials said Mr Sarkozy had undertaken to supply Pakistan with "civilian nuclear technology".
But the Elysee Palace said France had agreed only to co-operate in the field of "nuclear safety".
Speaking to reporters after talks between Pakistani President Asif Ali Zardari and Mr Sarkozy, Pakistan's foreign minister outlined what he called a "significant development."
"France has agreed to transfer civilian nuclear technology to Pakistan," Shah Mahmood Qureshi told reporters.
Mr Qureshi said the move was in recognition of the growing "energy crisis" in Pakistan, citing the need for nuclear power to guarantee the country's electricity supply.
But later a spokesman for the French presidency was careful to rein in expectations, saying Mr Sarkozy had "confirmed France was ready, within the framework of its international agreements, to co-operate with Pakistan in the field of nuclear safety."
"This is so the Pakistani programme can develop in the best conditions of safety and security," the French spokesman added, according to AFP news agency.
As well as a nuclear power station, Pakistan has nuclear weapons, but increasing turmoil in the country has caused concern among Western powers about its safety.
France is in fact not in a position to begin unilaterally transferring nuclear technology to Pakistan, says correspondent Hugh Schofield in Paris.
That is because Pakistan is not a signatory to the Nuclear Non-Proliferation Treaty and is therefore the object of a boycott from other nuclear powers.
India was in a similar situation, but last year negotiated its way back into the nuclear fold.
Pakistan would like to follow suit, Hugh Schofield adds, but concerns over the stability of the government there means that any suggestion of countries like France transferring new nuclear technology are bound to be highly controversial.
The two leaders also discussed aid for civilians fleeing fighting in Pakistan's north-west.
France pledged 12m euros ($16.3m; £10.7m) in humanitarian aid, a day after Britain promised £12m.
France also reiterated its support for Pakistan's fight against the Taleban and "terrorist groups" in the region.