Jean-Yves Le Drian told business leaders from the East Asian economic powerhouse the UK’s presence in the European Union is “finished” and Japanese companies operating in the UK should “assess their interests”.
The Frenchman went on to signal his country would attempt to woo any Japanese firms thinking about relocating from Britain after Brexit.
His comments come despite the fact the UK has yet to begin negotiations with Brussels on what a future trade relationship will look like.
Speaking in Tokyo on Monday, Mr Le Drian was asked a question about Britain’s divorce from the bloc.
In response, he said: “The message is clear: first of all, the presence of the UK in the EU is finished.
“Japanese companies must become aware of the consequences.
“It’s up to Japanese businesses to assess their interests and it’s up to us to say, ‘yes it’s over with the UK and this is what we will do to welcome you’.”
Japan is the world’s third-biggest economy and several of its well-known corporations, including car giants Nissan and Honda, operate factories in the UK.
Multinational conglomerate Hitachi also does a sizeable amount of business in Britain, and according to Japan’s ambassador in London, some 1,000 Japanese companies employ around 160,000 people.
Speaking last year, Koji Tsuruoka said the total investment from Japanese firms in the UK totalled about £60billion.
Japan’s Prime Minister, Shinzo Abe, was a vocal opponent of Brexit before the 2016 referendum and went as far as backing then-PM David Cameron and the Remain campaign.
Mr Abe raised concerns Britain would be “less attractive” to businesses from his country if the UK did not have tariff-free access to the rest of the EU.
But after the vote to Leave, he has since insisted he is “convinced” the UK will remain a “compelling” place for Japanese firms.
Speaking alongside Theresa May at a Japan-UK business forum in Tokyo in August 2017, Mr Abe said Brexit “has to be successful for the UK, European Union and global economy”.
But he called on negotiators from both the EU and Britain for a commitment on “transparency and predictable” during the Brexit talks to ensure businesses could continue to operate as normal.
Speaking in August, he said: “We have 1,000 companies operating in the United Kingdom.
“It is a base and they use it as a gateway to the European Union.
“So I have asked for greater transparency and predictability in this regard.”