The sailors had been in the French port city of Saint-Nazaire since June, training aboard the Vladivostok, the first of two Mistral-class ships whose delivery was delayed and then suspended in late November.
"The Russian sailors will return before the year-end holidays," a DCNS spokesperson said, adding there was "no delivery date" planned for the Vladivostok at the time being.
The delivery was indefinitely suspended after France came under pressure from its Nato allies not to deliver the warships, risking fines for not fulfilling a 1.2-million-euro contract signed between Russia and partly state-owned DCNS in 2011.
French President François Hollande said on 25 November "the current situation in eastern Ukraine still does not allow for the delivery" of the ship.
Russia has warned France of "serious consequences" if it fails to deliver the ships, but so far has not announced any specific legal or other action.
DCNS said the second ship, the Sebastopol, was still under construction.
By the terms of the contract, it would theoretically be delivered in October 2015.