The Sebastopol was eased from its Saint-Nazaire port in western France by tugboats just after 1:00 pm (1200 GMT) for a scheduled five-day test voyage without Russian navy personnel aboard.
The nearly completed "projection and command" warship is theoretically slated for delivery to Russia in the autumn of 2015 after undergoing a barrage of technical verification tests at sea.
But like the Vladivostok Mistral-class ship commissioned by Moscow under the same 2011 contract valued at 1.2 billion euros (USD 1.3 billion), the Sebastopol will be retained by France under Western sanctions against Russia for its support of separatists rebels in eastern Ukraine.
Testing scheduled during the Sebastopol's maiden outing was not revealed by authorities or the ship's STX builders.
