First designed in 1938, Lassen's My Own Chair features a separate winged back and seat that the brand says was "considered too progressive, even for the Modernists of the time, to be put into production".
Only one of the chairs was made for the yearly Cabinetmakers Guild Exhibition in Copenhagen, and subsequently sat in the architect's home. In 2014, the piece was auctioned in Denmark for €120,000 (£102,000).
By Lassen's new edition of the furniture is an "exact recreation", featuring the same sculptural back and wooden framework. It is available in textile or leather.
"My Own Chair perfectly highlights Flemming Lassen's love of rounded shapes, simple forms, precise detailing and functionality," said By Lassen.
Several brands have turned their attention to archive pieces, with Cappellini re-releasing a tubular chair created by Joe Colombo and Carl Hansen & Søn reissuing tables first designed by Poul Kjærholm in the 1950s.
Other brands are capitalising on products' lasting appeal by launching new versions, like Louis Poulsen's mini take on the 1971 Panthella lamp.
By Lassen is also issuing a second piece created by the architect in 1943. Based on an original drawing created for an interiors project, the Anoon drinks trolley features a removable chrome tray and wheels, with two levels of storage.
"When we first discovered this wonderful drawing from Flemming Lassen, we immediately felt that it matched many of the elements we find interesting when we begin to develop a product," said company director Nadia Lassen.
"I'm thinking here in particular about properties such as multifunctionality and flexibility."
The pieces will launch at Maison&Objet in Paris, alongside the brand's new Autumn/Winter 2016 collection, which includes patterned wallpapers based on original sketches by the architect, and a table with a reversible top.