French President Emmanuel Macron has warned that "there seems to be a European civil war" between liberal democracy and rising authoritarianism.
He urged the EU to renew its commitment to democracy, in a passionate speech to the European Parliament in Strasbourg.
"I don't want to belong to a generation of sleepwalkers that has forgotten its own past", he said, recalling how the EU arose after World War Two.
He is launching debates with voters, aimed at re-engaging them with the EU.
In his speech he condemned what he called "a fascination with the illiberal" in Europe.
Last year Mr Macron and his new liberal party, La République en Marche (LREM), triumphed in French elections with a strongly pro-EU platform.
His second-round rival in the presidential election was National Front (FN) leader Marine Le Pen, a nationalist and fierce critic of the EU.
Mr Macron was also hitting back at the Eurosceptics who drove the vote for Brexit in the UK.
As Brexit will leave a big hole in the EU budget he said there should no longer be budget rebates for some member states. He added that France was prepared to increase its contribution.
Mr Macron's set-piece speech in Strasbourg set out his vision for democratic renewal in the EU, at a time of growing nationalism in the 28-nation bloc.
This month Hungary's right-wing leader Viktor Orban, another arch-critic of EU policies, won a new two-thirds majority in parliament.
There is much nervousness in the EU about Russian influence on European voters, with many examples of fake news spreading in social media - often blamed on supporters of Russian President Vladimir Putin.
MEPs applauded Mr Macron when he said democracy "is a word with meaning, which emerged from the battles of the past".
He faces a big challenge ahead of the 2019 European elections as his LREM party does not belong to any of the main groups in the European Parliament, reports BBC.