The decision to suspend delivery of a Mistral naval assault ship to Russia risks costing France at least 1bn euros (£800m), officials say.
French President Francois Hollande said Russia’s actions in eastern Ukraine meant conditions were not right for delivery of the helicopter-carrier.
He later said « a ceasefire and a political settlement » should be in place before the deal could go ahead.
Russia was expecting two Mistral ships – the first one in October.
A French diplomat earlier said the contract was suspended until November, and the delay « could cost us 1bn euros ».
The deal is worth 1.2bn euros – and Russia is reported to have paid most of it, so breach of contract would mean France having to reimburse that money.
In addition, France would be liable for an extra 251m-euro penalty payment, French news website LCI reports.
The first ship is called the Vladivostok.
About 400 Russian sailors are training at the shipyard in Saint-Nazaire, western France, to be ready for the eventual handover of the Vladivostok.