As he continued to work for Cahiers, he made Une femme coquette (1955), a 10-minute short, in Geneva; and in January 1956 he returned to Paris. A plan for a feature film of Goethe's Elective Affinities proved too ambitious and came to nothing. Truffaut enlisted his help to work on an idea he had for a film based on the true-crime story of a petty criminal, Michel Portail, who had shot a motorcycle policeman and whose girlfriend had turned him in to the police, but Truffaut failed to interest any producers. Another project with Truffaut, a comedy about a country girl arriving in Paris, was also abandoned. He worked with Rohmer on a planned series of short films centering on the lives of two young women, Charlotte and Véronique; and in the autumn of 1957, Pierre Braunberger produced the first film in the series, All the Boys Are Named Patrick, directed by Godard from Rohmer's script. Une histoire d'eau (1958) was created largely out of unused footage shot by Truffaut. In 1958, Godard, with a cast that included Jean-Paul Belmondo and Anne Colette, made his last short before gaining international prominence as a filmmaker, Charlotte et son Jules, an homage to Jean Cocteau. The film was shot in Godard's hotel room on the rue de Rennes and apparently reflected something of the 'romantic austerity' of Godard's own life at this time. His Swiss friend Roland Tolmatchoff noted; "In Paris he had a big Bogart poster on the wall and nothing else." In December 1958, Godard reported from the Festival of Short Films in Tours and praised the work of, and became friends with, Jacques Demy, Jacques Rozier, and Agnès Varda—he already knew Alain Resnais whose entry he also praised—but Godard now wanted to make a feature film. He travelled to the 1959 Cannes Film Festival and asked Truffaut to let him use the story on which they had collaborated in 1956, about car thief Michel Portail. He sought money from producer Georges de Beauregard, whom he had met previously whilst working briefly in the publicity department of Twentieth Century Fox's Paris office, and who was also at the Festival. Beauregard could offer his expertise, but was in debt from two productions based on Pierre Loti stories; hence, financing came instead from a film distributor, René Pignières.
Godard wanted to hire the American actress Jean Seberg, who was living in Paris with her husband François Moreuil, a lawyer, to play the American woman. Seberg had become famous in 1956 when Otto Preminger had chosen her to play Joan of Arc in his Saint Joan, and had then cast her in his acidulous 1958 adaptation of Bonjour Tristesse. Her performance in this film had not been generally regarded as a success—The New York Times's critic called her a "misplaced amateur"—but Truffaut and Godard disagreed. In the role of Michel Poiccard, Godard cast Belmondo, an actor he had already called, writing in Arts in 1958, "the Michel Simon and the Jules Berry of tomorrow." The cameraman was Raoul Coutard, choice of the producer Beauregard. Godard wanted Breathless to be shot like a documentary, with a lightweight handheld camera and a minimum of added lighting; Coutard had had experience as a documentary cameraman whilst working for the French army's information service in Indochina during the French-Indochina War. Tracking shots were filmed by Coutard from a wheelchair pushed by Godard. Though Godard had prepared a traditional screenplay, he dispensed with it and wrote the dialogue day by day as the production went ahead. The film's importance was recognized immediately, and in January 1960 Godard won the Jean Vigo Prize, awarded "to encourage an auteur of the future". One reviewer mentioned Alexandre Astruc's prophecy of the age of the caméra-stylo, the camera that a new generation would use with the efficacy with which a writer uses his pen—"here is in fact the first work authentically written with a caméra-stylo".