Conservative Laurent Wauquiez, expected to become leader of France’s centre-right The Republicans party next month, has warned Brussels it needs urgent changes to survive.
And he called for the people to lead the direction of the bloc through a referendum.
Mr Wauquiez told the French daily Le Figaro: “If we want to save the EU, then we must deeply re-found the European project.
“Europe requires a new treaty, one which will allow the bloc to re-found and transform itself, and I think that France needs to put forward a proposal. This new treaty, however, must be put to the public in a referendum.
“Because, when dealing with something as complex as the need to re-found Europe, we cannot afford to go against the wishes of the people.”
Mr Wauquiez also said France’s staunchly pro-EU president Mr Macron was “wrong” to push for EU enlargement, calling instead for a “union of nation states”.
He said: “Mr Macron’s big mistake is to pit French sovereignty against the European project… to think we need more federalism. I on the other hand believe in a union of nation states.”
The tough right-winger also slammed Mr Macron for encouraging western Balkans states to apply for European membership.
He warned: “Europeans have expressed doubts over the benefits of further EU enlargement. The British, for example, have voted to leave the bloc. Europe is struggling to function effectively. It’s on the brink of collapse.
“With 27 members, Europe isn’t working. I call for a freeze on EU enlargement. No more countries should be able to join the bloc.”
Mr Wauquiez – who brushed off claims he is a staunch “Eurosceptic” and instead described himself as a “committed European” – also called for the bloc to reconnect with its “core values”.
He said: “Europe must reconnect with its core values and its civilisation. Because, once again, Mr Macron is wrong. There is no such thing as a European nation. There is, however, a European civilisation.”
The hard-right Republican also said that the EU should have a “core” of around 12 member states that would pursue closer cooperation on matters such as tax harmonisation, employment rights and social laws and policies.
Other members of the euro zone would form a second tier, and countries which are only interested in free trade would form a third tier. Post-Brexit Britain, Mr Wauquiez said, could be included in the third tier.
Mr Wauquiez also called for France to regain its territorial sovereignty, and for a “new Schengen agreement” which would take into account the need for tougher border controls in a bid to stem illegal immigration to Europe.