French President Emmanuel Macron said on Wednesday he had previously spoken to Japan's prime minister about the conditions former Nissan-Renault boss Carlos Ghosn was being held under, Reuters reports.
After fleeing Japan in late December, Ghosn said he had been treated "brutally" by Tokyo prosecutors and that he was the victim of a conspiracy by Japanese carmaker Nissan.
"I told (Prime Minister Shinzo) Abe several times that the conditions of Carlos Ghosn's detention and questioning did not appear to be satisfactory to me," Macron told reporters.
Ghosn told a press conference last week that he had fled to clear his name and said, without naming the president, that the seeds of the crisis at the Franco-Japanese carmaking alliance were sewn when Macron was economy minister.
Macron said on Wednesday decisions he had taken "had always defended French interests," adding that it was too convenient to argue that defending national interests could harm an executive.
Ghosn said Nissan and Japanese officials were shocked by a decision by the French government in 2015 to increase the state's shareholding in Renault and double its voting rights.
"This left a big bitterness," Ghosn said last week.
The move left the Japanese side of the Renault-Nissan alliance fearing that a national champion was falling under the control of the French government, sources have said.