The trip to Paris was planned weeks before May lost her majority in the election, but could not have come at a more welcome time for the Prime Minister.
May and Macron will announce joint plans to fine social media companies such as Facebook, Twitter and Google if they fail to remove extremist content from their websites.
However, May will hope to use the meeting to build significant bridges ahead of Brexit negotiations after Macron's predecessor, Franois Hollande, threatened to "punish" the UK.
There are fears that Macron, an ardent pro-European who is fresh from securing a landslide victory in the French parliamentary elections, could harden France's already tough stance on Brexit.
Brexit talks were due to open on Monday next week but Davis said yesterday that they are now likely to take place later in the week. The delay is because May needs to publish her Queen's Speech, which will set out her legislative programme, before she starts Brexit negotiations.
It emerged that the EU has warned May that it could take a year for Barnier to draft a new mandate for negotiations.
Such a long delay would make it almost impossible to complete negotiations before the end of the two-year negotiating period.
It came as Angela Merkel signalled yesterday that the triumph of Macron's new centrist party in the first round of France's parliamentary elections paves the way for deeper EU integration. The German Chancellor congratulated the French president on "a strong vote for reforms" as a Franco-German working group drafts proposals for closer eurozone cooperation to be presented next month.
Parties hold talks on soft Brexit
Senior British Cabinet ministers are engaged in secret talks with Labour MPs to secure cross-party backing for a soft Brexit, it has emerged.
Some of the most senior members of Theresa May's team have been plotting how to force the Prime Minister to make concessions on immigration, the customs union and the single market. There have also been discussions of a cross-party Brexit Commission to agree on common ground between the parties.
Labour is expected to use the talks as leverage to demand an end to the public sector pay freeze among a series of concessions in next week's Queen's Speech at the State Opening of Parliament. May is understood to have been "aware" of the plot for several days.
Ruth Davidson, the increasingly influential leader of the Scottish Conservatives, told May in a meeting yesterday that she must "reach out" to other parties and "work with others on Brexit". She added that there should be "changes in the offer on Brexit as we go forward". Michael Gove, the Environment Secretary, says it is vital that the Government can "achieve a deal that can command the widest possible support". May was cheered at the first meeting of the 1922 Committee of backbench Tory MPs as she told them: "I got us into this mess and I'll get us out of it".
Brexit will dominate whatever remains of May's premiership, and the Conservatives behind the talks with Labour MPs believe she will have no choice but to accept their demands in order to ensure her Brexit plans are not blocked by Parliament.
