A French aircraft carrier lined with asbestos is on a controversial voyage to an Indian breaker's yard in Alang, in the western state of Gujarat.
The Clemenceau: Decommissioned since 1997
Green groups have been protesting in France and India against the transfer. A number of protesters have been detained by Indian police in Delhi.
Last week a French court ruled that the old warship could set sail.
An official in the port of Toulon said the Clemenceau was on its way after a 24-hour delay due to bad weather.
The 24,200-tonne ship, which was taken out of service in 1997, is to be towed over the next two months to the world's largest ship-breaking yard in India.
Green activists protesting outside the French embassy in India accused France of sending an old military ship containing toxic waste.
"They are illegally dumping the ship on India," Greenpeace India activist Rampati Kumar told the Associated Press news agency.
"We call upon the French authorities to immediately call back the ship," he said.
Green groups say Indian ship-breakers are not properly equipped to deal with asbestos, which can cause lung cancer.
The French company charged with dismantling the ship has said the workers' health "will be taken into account".
The Clemenceau took part in the 1991 Gulf War, but was replaced in 1997 by the new nuclear-powered carrier, the Charles de Gaulle.