An official inquiry found no evidence of fraud. The agency is still pursuing investigations into FCA, Renault and PSA, however.

French authorities have closed an investigation into suspicions of Opel emissions violations.The country's Directorate General for Competition Policy, Consumer Affairs and Fraud Control collected and analyzed documents submitted by the automaker, along with test results from two independent labs.

"These elements ... have not revealed facts constituting an offense of fraud," the agency said in a statement.

The investigation was part of a broader inquiry that sought to survey nitrogen oxides emissions from a dozen vehicles sold in France.

The DGCCRF is still pursuing investigations into several other automakers suspected of cheating emissions regulations including Renault, Fiat Chrysler Automobiles and PSA Group.