Why France Insisted on Building Nuclear Weapons France’s interest in nuclear science was at first a quest for an energy source more than a weapon—an industrial nation needed fuel to power its armaments factories. Here's What You Need to Remember: After a very controversial series of underground tests in the Pacific France ended its nuclear testing for good and signed the Comprehensive Test Ban Treaty in 1998. With transatlantic alliances now in question the French president has reason to thank his predecessors for the bomb that gives France its independence. Once Europe had trembled under the tramp of French boots; twice Paris had fallen to a foe; three times France had succumbed to invasion. Before the World War II France, like Britain and Germany, led the way in nuclear science, building on the Curie family’s work. Frederic Joliot-Curie set up the first cyclotron or particle accelerator in Europe and with Lew Kowarski succeeded in creating a fission reaction in uranium early in 1939, soon after the discovery of the phenomenon.