France's finance ministry said in a statement on Thursday that France had seized a yacht owned by Russian oligarch Igor Sechin.
Sechin is the CEO of the Russian oil company Rosneft. The European Union earlier this week described Sechin as "one of the most trusted and close advisers to Russian President Vladimir Putin, as well as his personal friend".
The yacht, named "Amore Vero" - or "True Love" in Italian - arrived at the French Mediterranean port of La Ciotat in January. It was scheduled to leave port on 1 April.
French Finance Minister Bruno Le Maire said in a tweet: "Thank you to the French customs officials who are enforcing EU sanctions against people close to the Russian government."
Sechin was the Deputy Prime Minister of Russia from 2008 to 2012. The EU said its relationship with Putin was "long and deep", with the two men maintaining daily contact.
Earlier this week, Le Maire announced that France had set up a task force to complete a census of financial assets and luxury goods owned by Russian personalities targeted by EU sanctions.
BP said on Sunday it would exit its 19.75% stake in Rosneft and leave two seats on the company's board.