Shipowner and trader Vitol has rejected accusations of gas market manipulation in France.
CoRDiS, the disciplinary tribunal of French energy regulation committee CRE, said it had fined the company EUR 5m ($5.75m) for breaching the country's energy code.
"Vitol rejects the findings of CoRDiS and will be appealing," Vitol said.
"Vitol maintains that its trading strategies were appropriate to physical energy markets and in accordance with the applicable market regulations, as confirmed by expert evidence.
"Moreover, Vitol believes that CRE did not follow due process and, had it done so, the result would have been different."
It added: "Vitol believes that market integrity can only be achieved through the consistent application of logical, clear and transparent rules to all participants. This has not been the case in respect of CRE’s treatment of Vitol."
CoRDiS had ruled that Vitol manipulated the market between 1 June, 2013, and 31 March, 2014.
It cited 65 cases spread over 54 trading days, with alleged stacking of sales orders at the start of the day when liquidity was very low, and then the insertion of sales orders at lower and lower prices as the day went on.
Traders would then make purchases after prices had fallen and cancel sales orders, CoRDiS claimed.
