Opinion polls suggest Front National's Marine Le Pen is likely to top the first round of the presidential poll on April 23 but then lose the May 7 run-off to conservative Francois Fillon or centrist Mr Macron.
Speaking to Channel Four News, Mr Macron denied his stance would be a “punishment”.
Emmanuel Macron said he would be "pretty tough" on Brexit
If your government decides to organise a Brexit I will be pretty tough on it
He said: “If your government decides to organise a Brexit I will be pretty tough on it. We have to preserve the rest of the European Union and not to convey the message that you can decide to leave without any consequence.
“It’s not to be punished but to be consistent with such a decision. You don’t get the passport and you don’t get access to the single market when you decide to leave.”
Asked about the rights of British citizens living in France and how that might change if the UK government did not guarantee the rights of French citizens in Britain, Mr Macron added it was not “a game”.
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He said: “For sure, they are very welcome. The day after you have bilateral conventions to organise such a moment. It depends on the bilateral conventions the day they decide to leave the single market.
“But if they do decide to implement the Brexit in what Mrs May proposed, for sure, we have first to work at the European level and second to be extremely rigorous about the consequences because it cannot be a game where Britain can maximise their interests without taking into consideration the EU’s interests.”
Meanwhile, Austria's left-wing president branded people who voted for Brexit “crazy” and “not particularly intelligent” during an extraordinary rant in Brussels on Monday.
He has described his recent election victory against far-right candidate Norbert Hofer as evidence that you “can win against populism” and urged other EU chiefs to follow his lead.
Get to know Marine Le Pen Sat, January 28, 2017
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Marine Le Pen is a French politician who is the president of the National Front, a national-conservative political party in France and one of its main political forces.
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A French politician who is the president of the National Front (FN), a national-conservative political party in France and one of its main political forces.
Alexander Van der Bellen said: “You must be crazy to believe that the old fashioned national sovereignty of the 1930's gains you more power for your own country than being a member of the union.
“You don’t have to be particularly intelligent I don’t think to understand that.”
Mr Van der Bellen also alluded to his personal opinion on the issue of whether Europe should become a superstate, stating he did not want to describe meeting EU officials as a “foreign trip” because “we’re not really abroad when we’re in Brussels”.
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