President Sarkozy is the first head of state to visit Japan after March 11 earthquake which claimed more than 10,000 deaths and with more than 15,000 still missing.
Sarkozy, who is the chairman of the G20 and G8 economic groups will meet with Japan Prime Minister Naoto Kan on Thursday.
France has gained advanced nuclear technology over the years being host to at least 58 nuclear reactors all over France, making the European country the most nuclear-dependent state in the world. Around 75% of the country's power needs come from nuclear plants.
"We have sent two experts, one from the CEA and one from Areva to share our experience on pumping and the treatment of radioactive water," Environment Minister Nathalie Kosciusko-Morizet told reporters
The United States is also weighing in to send some radiation-detecting robots to Japan to help explore the reactor cores and spent fuel pools, the Energy Department said.
Earlier US barges were reported to have transported fresh water to the overheating Fukushima nuclear plant in an effort to cool the reactors with fresh water in lieu of the salty sea water the plant has been using the past several days.
"Workers at the stricken Fukushima Dai-ichi plant have been pumping seawater in a frantic bid to stabilize reactors overheating since a tsunami knocked out the complex's crucial cooling system March 11, mb.com.ph
"Plant operator Tokyo Electric Power Co. is rushing to use freshwater instead because of the corrosive potential of the salt in seawater, Hidehiko Nishiyama of Japan's Nuclear and Industry Safety Agency said at a briefing Saturday.", the report added.