This case arose out of a collision. On 5 March 2013, in very high winds, the sailboat Waka, which was moored to a deadman mooring post in Lazaret Bay, drifted and collided with the launch Yoyo, which was at anchor in port. The first vessel dragged the second vessel, and both then stranded on the rocks of the harbour breakwater. GMF Assurances (GMF), the insurer of the launch Yoyo, paid out its owner S, and then sought reimbursement from Y, the owner of the sailboat Waka, and from Y's insurer, GIE Navimut.

The Courts below rejected S's and GMF's claims. The basis for their judgment was that the liability regime in matters of maritime collision initially resulted from the Collision Convention 1910, supplemented by the Collision (Civil Jurisdiction) Convention 1952, and the Law of 16 July 1967 relating to incidents at sea. This regime was then codified in arts L 5131-1 ff of the Transport Code after Ordinance No 2010-1307 of 28 October 2010. According to art L 5131-3 of the Transport Code, if the collision is caused by the fault of one of the vessels, compensation for the damage is the responsibility of the person who committed it. If the collision is fortuitous, if it is due to a case of force majeure, or if there is doubt as to the cause of the accident, the damages are borne by those who suffered them, without distinguishing the case where either of the ships, or one of them, was at anchor at the time of the collision. Article L 5131-4 of the same Code specifies that if there is a common fault, the liability of each party is proportional to the gravity of the faults respectively committed. However, if, according to the circumstances, the proportion cannot be established, or if the faults appear to be equivalent, the responsibility is apportioned equally between the parties. The damage caused, either to the ships, or to their cargo, or to the effects or other property of the crews, passengers or other persons on board, are borne by the ships at fault, in this proportion, without joint and several liability with regard to third parties. Vessels at fault are held responsible jointly and severally vis-à-vis third parties for damage caused by death or injury, except for recourse by a party who has paid a higher share than it must definitively bear. Liability in matters of collision supposes not only fault and damage but also a causal link, the fault having to be the cause of the damage, ie of the collision. The mere contact between two vessels is not sufficient to create a presumption that one of them is at fault.

The Courts below held that it appeared from the expert report that the grounding and sinking of the Yoyo was linked to its collision with the Waka; but that did not demonstrate that Y was at fault for the mooring chain of the deadman mooring post breaking. The report showed that a sensitive part of the mooring chain was worn. It was not established that Y had an obligation to check underwater that the mooring system was in good condition, especially in very high winds. Consequently, by a combined application of the specific provisions of the Transport Code requiring the demonstration of a particular fault on the part of the person in charge of the vessel, and art 9 of the Code of Civil Procedure, S's and GMF's claims were rejected.

S and GMF appealed in cassation, arguing among other things that the Courts below erred in stating that 'the fact that Mr. [Y] did not inform the harbour master's office does not present any causal link with the collision', without seeking to establish whether there was indeed a causal link between the fault of Y, who did not contact the harbour master's office before mooring at the deadman mooring post which ultimately proved to be faulty, and the collision which subsequently occurred. They further contended that the Court erred in stating that 'the fact that Mr. [Y] left the ship in the early hours of the morning has no causal link with the collision', without investigating whether Y's choice to leave the Waka on 5 March 2013 at around 05h00 in very windy weather, without carrying out any surveillance from the coast, and not returning to the area until the morning of 6 March, without having contacted the harbour master's office in the meantime, were not directly causally related to the collision. Finally, they argued a breach of COLREGs, in particular r 5, as the Waka had not maintained an appropriate watch.

Held: Appeal dismissed.

The Courts below held that the sailboat Waka was not anchored, but moored to a mooring post in an area authorised for mooring, and that the collision with the launch Yoyo took place, not because of the breaking of the sailboat's mooring line, but that of the mooring chain at the level of the concrete block placed on the seabed, the solidity of which Y did not have to check. In adding that the fact that Y did not notify the harbour master's office, or that he left his sailboat, had no causal link with the collision, the Courts were demonstrating that the only possible fault imputed to Y was not having removed his sailboat from 'its entanglement in the anchorage' of the launch. This fault would have been committed after the collision itself, and could not have been its cause within the meaning of art L 5131-3 of the Transport Code. The Court of Appeal thus legally justified its decision to dismiss the fault, within the meaning of the aforementioned provision of the Transport Code, of the Waka in the occurrence of the collision.