## Facts

- On August 2, 1926, the French mail steamer *Lotus* collided on the high seas with the Turkish collier *Boz-Kourt* near Mytilene, Greece.
- The *Boz-Kourt* broke apart and sank; eight Turkish nationals died.
- The *Lotus*, under French command, assisted survivors and then proceeded to Constantinople, arriving August 3, 1926.
- Turkish authorities summoned and examined Lieutenant Demons, the French officer of the watch at the time of the collision, then arrested him.
- Turkey initiated criminal proceedings against Demons (and also against the Turkish captain) for negligent navigation causing death.
- France protested that Turkey unlawfully exercised criminal jurisdiction over a French officer for conduct occurring on the high seas.
- The dispute was submitted to the Permanent Court of International Justice by special agreement in 1926, requesting a ruling on whether Turkey’s prosecution violated international law (including Article 15 of the 1923 Lausanne Convention) and, if so, what reparation was owed.

## Issues

1. Whether international law reserved criminal jurisdiction over a high-seas collision exclusively to the flag State of the vessel on which the accused served, thereby barring Turkey’s prosecution of a French officer.
2. Whether Turkey could assert criminal jurisdiction based on the collision’s effects on a Turkish ship and Turkish nationals.
3. Whether Article 15 of the 1923 Lausanne Convention limited Turkey’s criminal jurisdiction over Demons for this incident.

## Decision

- The Court held, by a narrow majority, that Turkey did not act in conflict with international law by instituting criminal proceedings against Lieutenant Demons.
- The Court found no rule of customary international law or treaty rule that prohibited Turkey from exercising jurisdiction in these circumstances.
- The Court rejected France’s claim that the flag State’s jurisdiction over high-seas incidents was exclusive for mixed-nationality collisions.
- The Court concluded that Article 15 of the Lausanne Convention did not bar Turkey’s prosecution on these facts.
- Because no violation was found, the Court did not decide the question of pecuniary reparation.

## Legal Principles

- International law generally permits State action unless a prohibitive rule is shown; the burden rests on the objecting State to establish the restriction by treaty or customary law.
- A State may exercise criminal jurisdiction in its own territory over conduct occurring abroad when elements of the offense, including its effects, connect the matter to that State, and the accused is within its reach.
- High-seas incidents can give rise to concurrent jurisdiction; absent a specific prohibitive rule, more than one State may have competence to prosecute based on distinct jurisdictional links.
- A claimed customary limitation on jurisdiction requires sufficiently consistent State practice accompanied by a belief of legal obligation; isolated practice or practice from materially different situations is insufficient.
- Treaty-based limits on jurisdiction are not presumed; they must be supported by the treaty’s text and purpose.

## Conclusion

The Court upheld Turkey’s authority to prosecute a French officer for a high-seas collision that sank a Turkish vessel and killed Turkish nationals, reasoning that France failed to prove any prohibitive rule making flag-State jurisdiction exclusive or otherwise barring Turkey’s proceedings.


S.S. Lotus (Fr. v. Turk.), Judgment, 1927 P.C.I.J. (ser. A) No. 10 (Sept. 7)