Europe has to show 'solidity and strength' in its response to the economic and financial risks, the French president said after cabinet meeting.
Front National's Marine Le Pen, who displayed British flag on her Twitter page, said 'Bravo to the United Kingdom' after Britain's shock vote.
French president says quitting EU would put Britain at a 'very serious risk' of losing access to the bloc's single market.
Whichever way Britain votes in its referendum on EU membership this Thursday, French president François Hollande has promised new “initiatives” in the coming days to reinvigorate the European Union. Hollande himself has gone out on a limb by associating himself strongly with British premier David Cameron's opposition to so-called 'Brexit'. Meanwhile, as Lénaïg Bredoux reports, the French Left is itself split over the issue of Europe and how to approach it.
Series of polls show that between 32 and 41 percent of French population would see their neighbour's departure from EU in positive light.
French economy minister Emmanuel Macron warned that if Britain leaves the European Union it would have no clout with countries like China.
French economy minister warns that if UK left EU it must contribute to bloc's budget for trade deal and may not receive full access to single market.
Bernard Cazeneuve contradicted claims about impact of Brexit saying: 'We don't need statements that create buzz we need long-term action.'
Asked about impact of EU exit by UK on border controls in Calais, president said: 'I don't want to scare you .. but there will be consequences.'
Speaking at end of negotiations in Brussels, the French president added UK was not given veto over the eurozone 'which is very important for France'.
French president said there can be no special case for City of London nor restriction of EU migrants' rights, as demanded by UK PM David Cameron.
Seeking a deal ahead of 'Brexit' referendum, the UK PM met with President François Hollande in Paris in a bid to gain French backing for concessions.
The bank, which recently announced it is keeping its HQ in London, said global banking and markets staff could move to Paris if UK leaves EU.
As diplomatic efforts to keep UK in the EU gather pace before key Brussels summit this week, France heads campaign against City of London perks.
Economy minister Emmanuel Macron said creative ways can be found to amend EU treaties and prevent a European 'Brexit' crisis.