A trial of a US captain has begun in France after his cruiseship was alleged to have breached pollution limits.
Carnival Corp, the ultimate owner of P&O Cruises' 115,000-gt Azura (built 2010), is also on trial in Marseille, the Daily Telegraph reported.
It is the first such case in France.
Master Evans Hoyt, 58, has been charged with burning bunker fuel containing 1.68% sulphur, above the 1.5% limit.
He was prosecuted after a spot check and now faces up to a year in prison and a EUR 200,000 ($229,000) fine.
In court, his lawyer Bertrand Coste argued that European environment rules unfairly distinguished between cruiseships and cargoships, which have higher limits.
He said this meant a lack of "equality before the law".
Coste also sought to have the trial annulled due to alleged procedural errors.
"The defence is pulling out the stops so that the captain of the Azura escapes his responsibilities," prosecutor Franck Laugier said.
Defence lawyers also contend that the 1.5% limit does not apply to Azura as it is not a regular visitor to European ports. In this case, they argue the limit is 3.5%.
P&O Cruises told TradeWinds earlier this year: "We are committed to abiding by all applicable maritime standards and are confident that the current investigation will confirm this.
"We cannot comment any further until matters are resolved."
Hoyt was not in court. A ruling is expected on 26 November.
