The yacht was on its way back to the Mediterranean
The French military are continuing to track a luxury yacht seized, with its crew, on Friday by Somali pirates.
There has been no contact with the Ponant since it was boarded. French officials said they wanted to avoid using force.
French Prime Minister Francois Fillon said: "Our priority is to protect the lives of the people on board."
Somali coastal waters are among the world's most hazardous, with more than 25 ships seized by pirates in 2007.
"All channels of discussion are open to try to resolve this case by trying not to use force," Mr Fillon said during a visit to the city of Le Mans.
Earlier, defence minister Herve Morin said there had been no contact with either the crew of the vessel or the pirates.
The French coastal frigate Le Commandant Bouan had been sent to monitor the yacht, a military spokesman said. A Canadian helicopter on the HMCS Charlottetown also was taking part in the operation, the Associated Press (AP) said.
The Ponant - an 850-tonne three-masted yacht - was sailing back to the Mediterranean from the Seychelles when it was seized, officials said.
"As far as we know, no shots have been fired," French military spokesman Christophe Prazuck was quoted as saying by AFP news agency.
The yacht's owners - the shipping group CMA CGM - confirmed that one of its vessels had been seized.
The company said that the majority of the crew were French nationals, and the rest Ukrainian, AFP reported.
"I hope in the coming minutes or hours to try to win the freedom of these hostages," Mr Fillon said on Friday.
French and allied forces stationed in the area were put under alert.
France has troops in nearby Djibouti and also participates in a multinational naval force that patrols this part of the Indian Ocean.
The hijacked yacht can take up to 64 passengers and is designed for cruising in some style.
It has four decks, two restaurants and also indoor and outdoor luxury lounges.
In November, the French navy escorted two ships carrying food aid to Somalia to deter possible attacks from pirates.
In November 2005, pirates attempted to board a cruise ship carrying 600 passengers off the Somali coast.
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