On 24 February 2016, an oil slick was sighted in the French Exclusive Economic Zone (EEZ) in the wake of the Thisseas, a vessel under the Liberian flag. Laskaridis Shipping Co was summoned before the Criminal Court for the discharge of an oily polluting substance. Liberia informed France of the commencement of proceedings against the shipowners and operators of the vessel. Liberia requested a suspension of proceedings on French soil under art 228 of UNCLOS. However, the French Prime Minister did not respond favourably to this request. According to art 228.1 of UNCLOS:

Proceedings to impose penalties in respect of any violation of applicable laws and regulations or international rules and standards relating to the prevention, reduction and control of pollution from vessels committed by a foreign vessel beyond the territorial sea of the State instituting proceedings shall be suspended upon the taking of proceedings to impose penalties in respect of corresponding charges by the flag State within six months of the date on which proceedings were first instituted, unless those proceedings relate to a case of major damage to the coastal State or the flag State in question has repeatedly disregarded its obligation to enforce effectively the applicable international rules and standards in respect of violations committed by its vessels. 

The decision by which the coastal State objects to the suspension of proceedings is not to be dissociated from the conduct of its relations with the flag State. In the present case, the Criminal Court imposed a heavy penalty on the master and on the owner of the vessel. The Court adopted the theory of the act of state. This decision was appealed. The Court of Appeal of Rennes considered that the French judge had to verify whether the preconditions for the suspension of proceedings by France were fulfilled. Those conditions are the absence of serious damage, and the compliance of the flag State to its obligation to effectively apply the rules on pollution. For the Court of Appeal, these conditions were fulfilled, which led to the termination of the public action taken.

Held: The Court of Cassation rejected the argument of the Court of Appeal. For the Court of Cassation, the French Criminal Court cannot rule on France's decision to oppose the suspension of proceedings. Therefore, the Court of Cassation overturned and annulled the decision of the Court of Appeal. It referred the parties back to the Court of Appeal of Aix-en-Provence.