The information below indicates the US not only provided "how to build" nuclear weapons and missile information for France's purportedly "homegrown" nuclear deterrent, but the US provided this information on the understanding France would pass it on to Israel.
US TO FRANCE
William Burr https://www.wilsoncenter.org/person/william-burr wrote “U.S. Secret Assistance to the French Nuclear Program, 1969-1975: From "Fourth Country" to Strategic Partner” Dated May 26, 2011
at https://www.wilsoncenter.org/publication/us-secret-assistance-to-the-french-nuclear-program-1969-1975-fourth-country-to-strategic Extracts of this long paper include:
“The Nixon administration secretly reversed a policy of opposition to, and non-cooperation with, the French nuclear program that began to emerge during the final years of the Eisenhower administration [ie. late 1950s to 1961].
... Nixon's decisions stayed secret until the summer of 1989 when Princeton University political scientist Richard Ullman published an article in Foreign Policy magazine on "The Covert French Connection." 2 [Richard Ullman, “The Covert French Connection,” Foreign Policy, No. 75 (Summer, 1989), 3-33.]
...Supporting the decision to aid the French was the assumption, held by Nixon and national security adviser Henry Kissinger, that making French nuclear forces more effective would strengthen the U.S. strategic position against the Soviet Union.
Drawing upon interviews with over 100 former officials, Ullman sought to puncture two myths: that the French strategic force ["force de frappe"] was "entirely homegrown," and that, owing to Washington's restrictive policy on the diffusion of nuclear technology, only the British had been a recipient of direct assistance.
Recently declassified documents show that during the summer of 1973, French defense minister Robert Galley directly asked for "‘negative guidance' on the trigger for the French nuclear warhead."(Document No. 47)
Defense Minister Robert Galley brought up a variety of problems where the French wanted help, such as multiple reentry vehicles, hardening of reentry vehicles (RVs/warheads), "negative guidance" for nuclear weapons design, and developing underground test sites so that atmospheric tests could end. The aid that the French were seeking would amount to assistance for a new generation of French missiles. As Kissinger aide William Hyland observed, this meant "crossing a line that was observed during previous cooperation." (Document No. 48)
Yet, Ullman also notes that his interview subjects acknowledged that "they had no confidence that anyone really knew what American scientists and engineers said to French colleagues over lunch and dinner once they had been given a basic license to talk." 5 [Ullman, “The French Covert Connection,” 20.]
Thus, the actual conveyance of "negative guidance" may have been a matter outside of White House control. Certainly much more needs to be learned about the U.S. program of assistance to France.”
Pete Comment
Given US distrust of France’s independent foreign policy along with France’s independent nuclear program why was the US willing to help France. The joint enemy USSR was one reason. But I also theorise that French-Israeli nuclear cooperation in the 1950s (eg. France helping build the Negev/Dimona Nuclear Weapons Center and helping with Israel's Jericho missiles) continued in later decades.
In the 1960s, via France, the US secretly provide nuclear help to Israel, the US's most important strategic ally in the Middle East. US nuclear support to Israel occurring via France was more easily covered up. In espionage terms France acted as the deniable cutout for US nuclear weapon and missile intelligence to Israel.
FRANCE TO ISRAEL
Significant evidence of French nuclear assistance to Israel comes from a then serving US officer, who was both a military surgeon and military intelligence officer. He wrote about France’s early 1960s nuclear tests in the French Sahara. This was US Lieutenant Colonel Warner D. Farr, who in a 1999 report to the USAF Counterproliferation Center states "Progress in nuclear science and technology in France and Israel remained closely linked throughout the early fifties."
Furthermore, according to Farr, "There were several Israeli observers at the French nuclear tests [in the early 1960s in the Sahara] and the Israelis had 'unrestricted access to French nuclear test explosion data.'"[6]"
Pete Comment
So in the early 1960s there were Israeli observers to French nuclear tests of weapons that were built with US help.
Furthermore Israeli nuclear weapons scientists/engineers "had 'unrestricted access to French nuclear test explosion data."of nuclear weapons France built with US help. As Israel is not known to have conducted its own "hot" (ie. fission and fusion reaction) nuclear weapon tests Israel's nuclear weapons' development (via computer modelling) very much relied on French nuclear test explosion data.