The French president, Emmanuel Macron, has come under fire from political and secularist critics after calling for the country's notoriously divided church and state to 'mend' their 'damaged' relationship.

The issue is particularly sensitive in historically Catholic France, where the division was written into law in 1905 and which is now home to Europe's largest Muslim and Jewish communities.

Macron began a one-hour speech on Monday night to church dignitaries in Paris by saying that just arranging such a gathering was an achievement in itself.

'If we've done so, it must be because somewhere we share the feeling that the link between church and state has been damaged, that the time has come for us, both you and me, to mend it,' he said.

'I consider it my responsibility to stop the erosion of confidence among Catholics with regards to politics and politicians,' Macron added.

However, hardline leftist Jean-Luc Melenchon, a candidate in the election that brought Macron to power last May, said: 'It took three centuries of civil war and struggle to get to where we are and there's absolutely no reason to turn the clock back...because of an intellectual whim of the president's.' 

Former prime minister Manuel Valls and Socialist Party head Olivier Faure said the separation of church and state must remain a mainstay of political life, in a country where public service employees are banned from wearing Muslim veils and other dress with religious connotations.

Gay rights groups, who fought a bitter campaign against the Catholic Church over the introduction of same-sex marriage in 2013, were also critical.

Meanwhile, Macron came under attack from the right, too. Jean-Luc Mélenchon, leader of the far-left France Unbowed party, tweeted: 'We expect a president, we get a little priest.' Lydia Guirous, of the conservative Republicans party, said Macron 'is playing a dangerous game and does not understand the republic'.

Raised in a non-religious family, Macron was baptised as a Catholic at his own request when he was 12.

Around 55 per cent of French people define themselves as Catholic but fewer than five per cent attend church regularly.

Some French secularists are driven by a scepticism towards hard-line Islam, following a spate of terrorist attacks that have killed around 240 people since early 2015.

Macron is under mounting pressure to address voter fears that its influence may spread via mosques and prisons that reportedly offer fertile ground for radical proselytisers.

Prime minister Edouard Philippe responded in February by introducing prison isolation zones and more stringent licensing rules for faith-based schools.

France's guiding principles also hold that religious observance is a private matter, for all faiths.

Catholic leaders present for Macron's speech seemed less persuaded than his political detractors that they might soon again be exerting influence on government.

Cardinal Georges Pontier, who met the president on Monday night, told CNews TV he read the remarks as nothing more than an invitation to more open dialogue.

'Some people imagine the Church wants to take power over people's minds and more, but that's not true,' he said.

Additional reporting by Reuters.