France is deploying two Rafale fighter jets and a naval frigate in the eastern Mediterranean because of tensions between Greece and Turkey.
French President Emmanuel Macron has urged Turkey to halt oil and gas exploration in disputed waters in the area. A Turkish survey ship began such a mission on Monday, angering Greece.
Mr Macron told Greek Prime Minister Kyriakos Mitsotakis that the French military would monitor the situation.
The area is rich in untapped energy.
Turkish President Recep Tayyip Erdogan said the only solution in the Mediterranean was dialogue and that his country was not chasing adventure.
“If we act with common sense and reason, we can find a win-win solution that meets everyone’s interests,” he said.
There are also tensions around Cyprus over rival exploration rights. The Republic of Cyprus and Greece do not accept any such rights for Turkish-controlled northern Cyprus in the region.