The joy of achieving a certain je ne sais quoi gleams in Anthony Fabian’s heartwarming “Mrs. Harris Goes to Paris,” in theaters July 15, about a widowed ’50s-era cleaning lady—Lesley Manville’s affable Ada Harris — as she travels from London to Paris to purchase a Christian Dior gown. Designing the intricate costumes with exact Dior replicas was the job of Jenny Beavan, in another couture-centric film after her Oscar-winning designs for “Cruella.”

As a storyteller in her own right, Beavan was charmed by Mrs. Harris as a brave, hardworking woman pursuing her dreams. Portraying those with accuracy meant deep archival research, as well as a close collaboration with the House of Dior and its leading archivist, Soizic Pfaff.

Beavan was able to borrow five pieces from Dior’s Heritage collection for the movie’s central fashion show that Mrs. Harris attends to pick her eventual dress. They were mostly black-and-white frocks, remade in the ’80s and ’90s based on earlier originals. Those included the New Look-defining Bar Suit, introduced in 1947 with a full black skirt and narrow-waisted off-white jacket. In re-creating the garments with official Dior approval, Beavan and her team also collaborated with costume maker Jane Law and John Bright of costume supplier Cosprop. The green, strapless, intricately beaded Venus gown and red, tea-length, shimmery V-neck Temptation number that mesmerize Mrs. Harris were original designs that maintained the spirit of Dior.

Finding proper fabrics to attain the desired sculptural quality was a challenge. “We were in lockdown,” Beavan remembers. “I was very reliant on what Jane and John had in their stocks.” The top-notch crew of dyers and cutters studiously echoed Dior’s classic features, mirroring the brand’s archetypal interior underpinnings to give the work the appropriate shape.

Creating Mrs. Harris’ everyday wardrobe as a put-together woman with limited means was crucial. Vintage pieces from Cosprop accounted for most of the soft prints, optimistic colors and floral accents that Manville wore. Beavan often paired the clothes with thick stockings to make them look more homely. For further authenticity, she backdated Mrs. Harris, a person who’d make her clothes last for a long time: “She’s more ’40s than ’50s, with a lovely waisted coat.” As Mrs. Harris spends more time in Paris, the team gradually elevates her look with sophisticated pieces the character borrows from the sister of her temporary Dior roommate (played by Lucas Bravo). “But we kept her shoes — the ‘Mrs. Harris’ shoes,” Beavan adds.

Beavan shares a humorous detail pertaining to the Venus gown, which had to accidentally burn in one scene. “Looking at Dior around that time, he often did a flounce at the front and a tulle. [But] we managed to choose a tulle that absolutely refused to catch fire,” Beavan says. “The silk caught fire instead. At least something did.”