French fashion designer Jacques Heim, who owned a beach shop in the French Riviera resort town of Cannes, introduced a minimalist two-piece design in May 1946 which he named the "Atome," after the smallest known particle of matter. The bottom of his design was just large enough to cover the wearer's navel.

At the same time, Louis Réard, a French automotive and mechanical engineer, was running his mother's lingerie business near Les Folies Bergères in Paris. He noticed women on St. Tropez beaches rolling up the edges of their swimsuits to get a better tan and was inspired to produce a more minimal design. He trimmed additional fabric off the bottom of the swimsuit, exposing the wearer's navel for the first time. Réard's string bikini consisted of four triangles made from 30 square inches (194 cm²) of fabric printed with a newspaper pattern.

When Réard sought a model to wear his design at his press conference, none of the usual models would wear the suit, so he hired 19 year old nude dancer, Micheline Bernardin, from the Casino de Paris.He introduced his design to the media and public on July 5, 1946, in Paris at Piscine Molitor, a public pool in Paris. Réard held the press conference five days after the first test of a nuclear device (nicknamed Able) over the Bikini Atoll during Operation Crossroads. His swimsuit design shocked the press and public because it was the first to reveal the wearer's navel.