France's Energy minister Segolene Royal has said tests conducted on Renault cars had not shown any presence of fraudulent emissions concealing software.
France carried out testing to establish whether vehicles on its roads were possibly equipped with banned software, the kind used by Volkswagen in the United States to trick emissions tests.
"There is no fraud at Renault. Shareholders and employees should be reassured," Mr Royal told journalists.
The minister added that presence of C02 and NOx above accepted limits had, however, been detected in cars of other manufacturers.
Earlier, the Frence carmaker said fraud investigators were looking at the way it uses exhaust emissions technology in an additional probe of parts and factories that follows an earlier investigation by the French government.
Renault said investigations to date had found "no evidence of a defeat device equipping Renault vehicles."
The statement came after a union official revealed that the company's offices were searched last week by fraud investigators, news that sent the company's shares down by over 20%.
Renault shares were recording their worst day since November 17, 1994 and saw some €5 billion wiped from its market capitalisation, according to Reuters data.
German carmaker Volkswagen last year admitted to using software to conceal the level of toxic emissions from some of its diesel vehicles in the US.
It faces billions of dollars in claims from owners of vehicles with similar software installed around the world.
That has prompted investigations across several countries into Volkswagen, but also into other automobile manufacturers to ensure they have abided by regulations.
Meanwhile, French carmaker Peugeot said emission tests carried out by the Energy Ministry on its cars showed no anomalies and that it had not been subject to searches by fraud investigators.
