PARIS — The French have been ideally positioned to take advantage of the growing rift in recent weeks between the Arab monarchies of the Persian Gulf and the United States. Representatives of those monarchies met with President Obama on Wednesday to discuss their differences and especially their worries over a proposed nuclear deal with Iran.

Just days ago, France’s foreign minister, Laurent Fabius, said that French officials were working on memorandums of understanding for “several tens of billions of euros” in projects in Saudi Arabia. Last week, President François Hollande was warmly welcomed at a meeting of the Gulf Cooperation Council, where he oversaw the signing of a $7 billion deal to sell fighter jets to Qatar.

The gulf states are irate over Mr. Obama’s determination to reach a nuclear deal with Iran, a Shiite country and regional rival that would be strengthened by the end of sanctions. Under the deal, sanctions would be lifted in exchange for Iran’s agreement to greatly slow its nuclear program. By loudly voicing doubts about the pact, analysts say, France has made itself an advocate of gulf nations while drumming up business for its own arms industry.

“By appearing slightly tougher than the rest of the Western coalition on the nuclear deal, the French find a niche for themselves, a window of opportunity,” said Dominique Moïsi, a political scientist specializing in international affairs and a founder of the French Institute of International Relations. “And by buying French, the Saudis are also showing their displeasure with the Americans.”