French authorities have accused Fiat Chrysler Automobiles of "aggravated deceit" for allegedly obstructing that country's investigation into potential diesel emissions cheating.

According to reports from Reuters, Automotive News and elsewhere, the emissions of three small diesel engines found in FCA vehicles sold in France are being investigated by consumer protection officials. The officials have accused FCA of obstructing their work between May, 2016 and January of this year, according to documents signed by an investigating judge on Oct. 17.

France decided to do its own investigation of diesel emissions after the Volkswagen engine cheating scandal broke worldwide. The French Directorate-General for Competition, Consumption and Repression of Fraud (the DGCCRF) was assigned to do the work.

The other manufacturers targeted were co-operative - including Renault and PSA. FCA was not, according to court documents. The engines in question are the 1.3 and 1.6 Multijet II engines found in the Fiat 500 and Fiat Doblo van, and the 2.0-litre that powers the Jeep Cherokee.

The charges are described as serious on this crime site , and the consequences to FCA for being found guilty are huge - up to 10.5 billion Euros.

But the wheels of French justice can grind as slowly as any other, and there are no less than three judges involved along with a host of French bureaucracies. In FCA's defence is the possibility that investigators were fooled by software safe modes its diesels which kicked in to protect the test engines from damage.