It is alleged that the car produced NOx emissions of 585mg/km, rather than the 80mg/km it was understood to produce, when tested on the roads in December by a research centre commissioned by the European Commission.
In addition, under laboratory conditions, outside of the normal test temperatures of 17-23deg celcius, three times the permitted NOx emissions were produced, claims the French newspaper.
It is reported that the PSA Group, parent company of Citroën, DS and Peugeot, has sent its vice-president, Christian Chapelle, to explain the results to the European Commission.
Lucia Caudet, Commission spokesperson for internal market, industry, entrepreneurship and SMEs (small and medium-sized enterprises), said: "In the third quarter of 2016, the Commission's in-house Joint Research Centre (JRC) took a number of emissions measurements on four cars in the laboratory and on the road. The JRC took measurements on three diesel cars and one petrol car. These cars were selected randomly and they were of different models, years, mileage and mostly rented, hence the measurements are not indicative of particular concerns nor representative of entire fleets.