Paris When It Sizzles was based on the 1952 French film La fête à Henriette, which was released in the U.S. as Holiday for Henrietta in 1955. According to the 4 Feb 1962 NYT, Audrey Hepburn would reteam with Sabrina (1954, see entry) co-star William Holden and Breakfast at Tiffany’s (1961, see entry) screenwriter George Axelrod to develop the remake at Paramount Pictures. While the final release title was borrowed from a line in the Cole Porter song, “I Love Paris,” several contemporary sources listed the following working titles throughout pre-production: Holiday in Paris; Together in Paris; and The Girl Who Stole the Eiffel Tower, which is the name of the screenplay Hepburn and Holden’s characters write within the film.
       According to a 13 Jul 1962 DV production chart, principal photography began 18 Jun 1962 in Paris, France. The 11 Aug 1962 LAT claimed that neither Hepburn nor Holden were satisfied with Axelrod’s script, and hired writer-director Charles Lederer, who was vacationing in Paris, to compose a new draft. Lederer supposedly received $25,000 for one week’s work. During this time, Holden “disappeared” from the production for three weeks, but approved the rewrites upon his return. An 8 Aug 1962 LAT news item suggested that this absence may have been attributed to minor eye surgery to remove a cyst, after which he was required to re-shoot several scenes. However, as Tony Curtis explained in his 2008 memoir, American Prince, Holden had been forced to check into a rehabilitation clinic to be treated for alcoholism. Curtis’s character was subsequently written into the script in order to relieve screentime from Holden, who drank heavily throughout production. By contrast, an 11 Sep 1962 LAT news story publicly claimed that Curtis’s involvement resulted from the filmmakers' dissatisfaction with the French actors who auditioned to play Hepburn’s onscreen boyfriend, described in the script as a “Tony Curtis type.” The story alleged that Curtis himself volunteered for the role while on vacation in Paris.
       Around this time, the 29 Aug 1962 Var reported that director of photography Claude Renoir quit the project after Hepburn, feeling that her scenes were “somewhat lacking in polish,” had invited Charles Lang, Jr. to supervise his work. When Lang assumed the position, several members of the crew wanted to leave in solidarity with Renoir, who convinced them to remain with the project.
       An article in the 23 Sep 1962 NYT reported that Paris-area locations included Place Dauphine, Ile de Cité, Bois de Boulogne, Champs-Elyseés, Avenue Matignon, the Quai du Voltaire hotel, a terrace apartment on the Avenue George V, and Les Yvelines, outside the city. The 8 Aug 1962 LAT stated that rain prevented the crew from filming the annual Bastille Day ceremonies at the Place Dauphine, so the celebration was recreated on a soundstage at the Studios de Boulogne.
       Several French actors appeared in the picture, including Michel Auclair, who played the leading role in La fête à Henriette. While he may not have been credited onscreen, the 15 Aug 1962 NYT reported that he portrayed a French newspaperman in the American version. A 3 Jul 1962 DV brief also noted that Jonathan Harris had been signed for a co-starring role, but his involvement in the final film could not be determined. According to the 26 Aug 1962 LAT, local casting directors struggled to find two Native American Indians to be featured in a chase sequence through the Bois de Boulogne. Filmmakers reportedly approached two Seminole tourists from Florida, but they were unable to participate.
       Contemporary reviews, including the 18 Mar 1964 Var and 9 Apr 1964 NYT, noted that several members of the cast also perform roles in the film-within-the-film, while the voice of Frank Sinatra can be heard singing a line of a song for The Girl Who Stole the Eiffel Tower, intended as a parody of opening title themes. Hepburn’s husband Mel Ferrer, Marlene Dietrich, and Noël Coward also made uncredited cameos, and Fred Astaire sings offscreen.
       The 29 Jun 1962 DV stated that William Holden’s teenage son, West Holden, served as a still photographer on the set.
       Despite plans for a summer 1963 release, the 24 Jul 1963 Var announced that Paramount had pushed the opening to early 1964, citing the need for a more elaborate advertising campaign. Items in the 18 and 23 Sep 1963 DV reported that “sneak” previews were held in San Francisco, CA, the weekend of 21-22 Sep 1963. Conflicting accounts in the 7 Feb and 25 Mar 1964 editions indicated that a 300-400-theater release was expected for the Easter weekend, but the film did not debut until 8 Apr 1964.
       According to a 22 Jan 1964 Var, Dell Books issued a paperback novelization using a tie-in cover image and promotional advertisements in fan magazines.