Forty years later, the production techniques pioneered by Citroën had permitted the auto-industry to become one of the most important sectors in the industrialising economy, and auto-production had become massively labour-intensive.

Commercial success for the 2CV and (more recently) DS models left Citroën desperately short of production capacity in their cramped Paris site, and the decision was taken to build a new greenfield plant.

The Rennes location was chosen in 1958 on account of its abundant supply of available labour and the low wages in an area where the economy was heavily dependent on the primary sector.

Citroën's decision to build their new plant on a Greenfield site in an area still dominated by agriculture mirrored auto-industry developments taking place at this time in Michigan and several adjacent states in the USA.

Other reports apparently based on company press releases have suggested a rate of 55 cars per hours for the extensively upgraded new production line.

The sector has been under attack from luxury automakers such as Audi and BMW while more cost conscious buyers have been switching to smaller family cars in the Golf / Peugeot 308 class.

The site is a large one, and since February 2014 it has accommodated a substantial workshop for the renovation of High-speed trains, staffed by employees on assignment the SNCF from the PSA workforce.

Models principally produced up to the end of 2005 (figures rounded): Prior to 1999 the PSA group owned a second plant at Rennes dedicated to the production of rubber based components for the automobile industry.

The plant was sold to an Italian company in 1999, since when its ownership structure has charted a far from simple course:[6] currently "Barre Thomas" is owned by an investment fund called Silver Point.