Styled by Patrick Le Quément, the Avantime was intended to combine the space of an estate with the four place pillarless qualities of a coupé.

[5] Regarding the styling, Thierry Metroz, design project manager, said, "We wanted someone walking around the car to be continually astonished."

The windows and panoramic sunroof could open automatically via a single headliner-mounted control,[4] to give the Avantime an 'open air' mode of previous decades hardtop coupes and sedans.

The design borrowed the automotive space frame of the first generation Renault Espace (load bearing galvanized structure with non-load bearing composite panels) and used the PSA 24 valve, 207 hp (152 kW) 3.0L V6 engine, which was coupled to a six-speed manual transmission or five-speed automatic transmission.

[11][12] The Avantime was first shown in February 1999, in concept form at a press launch in the Louvre, and one month later to the public at the Geneva Auto Show – where it was referred to as a "Coupéspace"[5] – and went into production two years later, after the subsequent engineering of the pillarless roof to meet safety standards.