The Prime Minister flew to the French capital after breaking off from negotiations with the Democratic Unionist Party to shore up her minority government following last week’s disastrous election results.
Mrs May and Mr Macron said they discussed Brexit, security issues and migration.
Mrs May, speaking at a press conference, said: “We have been very clear we want to maintain a close relationship and a close partnership with the EU and individual member states into the future, including in the areas we’ve discussed this evening.
“And I confirmed to President Macron that the timetable for the Brexit negotiation remains on course and will begin next week.”
Mr Macron said France wants the negotiations to start as “quickly as possible”, later saying: “Of course the door remains open, always open until the Brexit negotiations come to an end.”
He added: “That being said a sovereign decision was taken by the British people and that is to come out of the European Union and I very much respect the decisions taken by the people, be it by the French people or the British people.
“As a matter of fact in this case it’s not for me to say whether or not this decision should be questioned - the decision to leave the European Union - but until the negotiations come to an end, of course there is always the possibility to re-open the door.
“But let us be clear and organised and once the negotiations have started we should be well aware that it’ll be more difficult to move backwards.”
Mrs May said last week’s General Election revealed “a unity of purpose” among British voters for the Government to get on with Brexit.
She said: “I think there is a unity of purpose among people in the United Kingdom.
“It’s a unity of purpose, having voted to leave the EU, that their Government gets on with that and makes a success of it, and we are committed to developing a deep and special partnership with the EU.
“We want the EU to continue to remain strong and we want to continue to cooperate.”
Mrs May said there was a “willingness and intent on both sides” to secure an arrangement for Brexit and there was a “good process” for the negotiations.
Mrs May was accompanied to Paris by Home Secretary Amber Rudd, with plans to stop the internet being a safe space for terrorists under discussion.
These include internet companies such as Facebook, YouTube and Google potentially being fined if they fail to remove extremist propaganda and terrorist material from their platforms.
The UK and France are also to develop plans to create a new legal liability for tech companies which fail to take action against unacceptable content.
And the two countries will lead joint work with internet giants to explore the potential for new tools to identify and remove harmful material automatically.
Ms Rudd and French interior minister Gerard Collomb will meet in the coming days to drive the agenda forward.
Mrs May and Mr Macron were later due to watch the France v England football friendly international at the Stade de France, where crowds are expected to sing God Save The Queen and observe a minute’s silence in honour of the victims of recent terror attacks in the UK.
The gesture of solidarity comes after English football fans sang the French national anthem at Wembley following terror attacks in Paris in 2015.