PARIS — The French Foreign Ministry confirmed Friday that an Iranian deputy foreign minister would attend the May 6 reconstruction conference in Marseille, completing a guest list European diplomats described as the most ideologically diverse Mediterranean gathering convened on a Middle East file in more than a generation and lifting a significant question mark off the most ambitious European diplomatic initiative since the Islamabad ceasefire.

Foreign Minister Stéphane Séjourné told reporters at the Quai d’Orsay that Tehran had formally accepted the invitation extended last week, naming Deputy Foreign Minister for European Affairs Majid Takht-Ravanchi as the head of its delegation. Israel, in a parallel exchange of notes received in Paris on Thursday evening, named Deputy Foreign Minister Sharren Haskel to lead a three-person delegation. The two ministers will not share a plenary table — French organizers said working groups had been structured to allow engagement on technical files without direct bilateral encounters — but both governments have committed to being present in the same conference hall for the opening session.

“Marseille will not deliver a treaty,” Séjourné said. “Marseille will deliver a structure. A structure in which money, mine-clearance teams, port engineers, refugee processors and insurance underwriters know where to send their requests, who answers them, and on what timetable. That is the bureaucratic spine a ceasefire of this fragility needs in order to last.”

The conference, scheduled for May 6 and 7 at the Palais du Pharo overlooking the Vieux-Port, will gather foreign ministers from twenty-two countries, finance officials from sixteen, and reconstruction coordinators from a dozen multilateral institutions. The Pakistani-Saudi-Egyptian mediation troika that drafted the Islamabad framework will be represented, as will the African Union, the Gulf Cooperation Council, the U.N. Development Programme and the International Atomic Energy Agency. France has set out a four-track agenda covering civilian infrastructure financing, displaced-population return, Mediterranean shipping insurance and what officials are calling, in deliberately vague language, the “post-conflict information environment.”

European officials privately acknowledged that the participation of both Iranian and Israeli deputy foreign ministers in the same building amounted to the most consequential signal of the day. Iran had not formally responded to the French invitation as recently as Tuesday, and several European foreign ministries had begun drafting contingency communiqués that would have characterized Tehran’s absence as a setback. Israel’s confirmation, which arrived first, was itself the subject of intensive shuttle diplomacy by Italian Foreign Minister Antonio Tajani and an emissary from the German chancellery, two European officials said.

“This is not a peace process,” said Hugo Meijer, a senior fellow at the Institut Montaigne, in an interview Friday. “Marseille is not Madrid in 1991. But for two governments whose missiles were striking each other’s cities six weeks ago to put a deputy foreign minister into the same room of the Palais du Pharo, in a working setting, is not nothing. It is the kind of opening French diplomacy is historically good at engineering and historically poor at converting into durable outcomes.”

Saudi Foreign Minister Prince Faisal bin Farhan will attend in person, leading a delegation that includes Saudi Aramco’s chief financial officer and the kingdom’s reconstruction envoy for Yemen, Mohammed Al Jaber. The United Arab Emirates confirmed Foreign Minister Sheikh Abdullah bin Zayed; Qatar named Prime Minister Mohammed bin Abdulrahman Al Thani, a sign of the prominence Doha attaches to its role in last week’s prisoner exchange. Pakistan will send Foreign Minister Ishaq Dar; Egypt, Foreign Minister Badr Abdelatty.

The United States will be represented at a deputy-secretary level, French officials said, in what European diplomats called a “deliberately calibrated” choice of seniority. A senior State Department official, speaking on condition of anonymity to discuss internal deliberations, said Washington wanted “the European bandwidth on this” and would coordinate closely on verification but would not lead financing or political guarantees. “Marseille is a European show,” the official said. “We are friends in the audience.” The White House has so far pledged no new reconstruction money beyond the $400 million Congress approved on April 11 for emergency humanitarian operations.

Russia and China, whose endorsement of the Islamabad framework will be sought at the U.N. Security Council next week, are each sending deputy foreign ministers. Russian Deputy Foreign Minister Mikhail Bogdanov will lead the Russian delegation. China named Vice Foreign Minister Deng Li, who has been quietly active in Gulf reconstruction conversations since early April, according to two diplomats in Riyadh.

The African Union’s choice of representation drew unusually high attention. Commission Chairperson Moussa Faki Mahamat will attend, accompanied by the AU’s commissioner for labor and migration — a deliberate signal, AU officials said, that the post-war agenda includes the Gulf-Africa labor corridor at the center of an AU-GCC ministerial dialogue this week. The Marseille declaration is expected to include language on remittance corridor protection that AU diplomats have been quietly drafting since East African return flights began last weekend.

The “post-conflict information environment” track is the most novel of the four working groups. European officials said the awkward phrasing was chosen to encompass, without explicitly stating, the bloc’s concern that disinformation and deepfake audio attributed to senior officials could destabilize the ceasefire in its first months. “We saw what happened in Lebanon on April 14,” said Sabine Verstraete, a Belgian diplomat who chaired the preparatory committee for the track. “An audio file circulated that purported to be a senior Israeli official ordering a strike. It was fake. It nearly broke the ceasefire forty-eight hours before it took effect. We cannot have a Marseille that ignores that.”

The Iranian delegation’s confirmation came with conditions, French officials acknowledged. Tehran will not engage in plenary statements that single out Iranian conduct during the war; the IAEA’s participation will be limited to a technical briefing on nuclear-site verification protocols already endorsed by the Islamabad framework; and any Israeli intervention referencing specific Iranian facilities will be channeled through the French chair. “Diplomacy is choreography,” a Quai d’Orsay spokesperson said. “We have the choreography.”

The European Union’s high representative, Kaja Kallas, will travel to Marseille from Brussels on May 5 and hold preparatory bilateral meetings with the Iranian and Israeli delegations on the conference’s eve. Officials said additional details on working-group chairs and the full draft declaration would be released in Paris and Brussels in the days before the conference opens.