The French president, Nicolas Sarkozy, is facing a row over a major arms deal with Libya signed a week after he secured the release of six imprisoned health workers held in the country.

Mr Sarkozy has repeatedly denied promising the weapons to Tripoli as part of a secret trade-off for the prisoners' freedom.

He faces fresh controversy after the European defence and aerospace giant EADS announced it had signed a €296m (£200m) military deal with Libya.

News that the weapons sale had been "finalised" came just two days after Saif ul-Islam, the son of the Libyan leader, Muammar Gadafy, suggested Tripoli had been promised arms.

François Hollande, the leader of the French Socialist party, demanded a parliamentary enquiry to "throw light" on the negotiations between Paris and Tripoli.

He questioned whether it was morally right to "have an arms trade with a country run by Gadafy, who has been responsible for terrorist attacks".

Mr Sarkozy sent his wife, Cécilia, to negotiate the release of five Bulgarian nurses and a Palestinian doctor who had been held in jail for eight years on charges of deliberately infecting hundreds of Libyan children with the Aids virus.

A day after they were freed, he flew to Tripoli and signed an agreement to help Libya build nuclear power stations, but made no mention of arms deals and heralded the prisoners' release as a triumph of French and European diplomacy.

The news that EADS - which is 15% owned by the French government - had "finalised" the deal to sell French-designed Milan anti-tank missiles came 48 hours after Saif ul-Islam Gadafy told Le Monde that Libya would be buying the anti-tank missiles from France.

He was also reported as saying he did not believe the foreign health workers were guilty, but had been "scapegoats".

The comments led to renewed demands for Mr Sarkozy to come clean on exactly what the Libyans had been promised.

The French government has been anxious to portray the deal as an agreement between a company and a country, which it said had been on the cards for many months.

EADS said the agreement was with its MBDA subsidiary, and was awaiting Libya's signature. MBDA is a joint venture between EADS, Britain's BAE systems and the Italian defence company Finmeccanica.

A second contract, for an advanced communications system, was "in the process of being finalised", an EADS statement said.

David Martinon, Mr Sarkozy's spokesman, told Le Parisien newspaper: "If commercial contracts have been signed between Libya and French companies, we can only congratulate them.

"Should we reproach national firms for winning business with a partner, Libya, which respects its international obligations?"

However, Libyan officials are keen to play up the deal as a bilateral agreement with France that marks their country's return to the international fold, as promised by Mr Sarkozy.

Mr Hollande conceded that the arms sales were not illegal, but demanded to know more about their provenance.

"We were told there was no bartering," he told French radio. "Then we learn the there was a civil contract over a nuclear reactor. I questioned the foreign affairs minister about this and a vague memorandum was given to us, but nothing about an arms contract.

"There's a real problem with method here. How can we, in a democracy, accept that Nicolas Sarkozy wants to be transparent when it's Gadafy's son who announces an arms contract has been signed, when the minister of foreign affairs knows nothing and the defence minister is still talking about a letter of intent.

"In a democracy such as our, transparency must be the rule."