[1] He took over the business in 1923, and within a year had added a couture department,[3] designing dresses and coats, made with original fabrics, working in collaboration with Sonia Delaunay.

[3] In 1932, Heim created a two-piece swimsuit consisting of a bra with ruffles and pretty bloomers, which he called the Atome.

[5] He was harassed during the Nazi occupation of France, but managed to stay in business by putting a non-Jewish "front man" in charge of his fashion house.

His most prominent clients were Sophia Loren, Queen Fabiola of Belgium, Mamie Eisenhower and actress Gloria Swanson.

[6][8] Heim served as President of Chambre Syndicale de la Couture Parisienne (Paris Fashion Trade Association) from 1958 to 1962.