The case arose from a collision on the high seas between the French vessel S.S. "Lotus" and the Turkish vessel S.S. "Boz-Kourt," which resulted in the sinking of the Turkish ship and the death of several Turkish nationals. Turkey subsequently prosecuted the French captain of the "Lotus" for the incident. France contested Turkey's jurisdiction, arguing that the case should fall under French jurisdiction since the incident occurred on the high seas.

• 1. Whether Turkey had the right to exercise criminal jurisdiction over a foreign national (the captain of the "Lotus") for actions committed on the high seas. 2. The validity of Turkey's claim of jurisdiction based on the principles of international law.

The PCIJ observed that international law permits states to exercise jurisdiction under specific conditions, particularly when national interests are involved. The Court noted that while the high seas are generally free from national jurisdiction, Turkey's right to assert jurisdiction was justified due to the nationality of the victims and the impact on Turkish interests. The Court emphasized that no specific rule of international law prohibits a state from prosecuting a foreign national for actions affecting its citizens.

The Court ruled in favour of Turkey, holding that Turkey had the right to exercise jurisdiction over the French captain of the "Lotus" based on the circumstances of the case. The judgment established the principle that states may exercise jurisdiction in cases where there are significant connections to their national interests, even if the acts occurred on the high seas. The principle established in the Lotus case regarding jurisdiction over incidents on the high seas changed with the introduction of Article 11 of the Convention on the High Seas, adopted in Geneva in 1958. This convention clarified that only the flag state of the vessel or the state of nationality of the alleged offender has jurisdiction over sailors involved in incidents occurring on the high seas. terms, by the competent authority, which was not present in this case.