When the trip was first planned, May hoped to be coming to France with a mandate for a tough stance in Brexit negotiations following last week's general election in the UK.
But she has ended up weakened, leading a hung parliament after her Conservative Party lost seats and the opposition Labour Party did unexpectedly well.
At 39, Macron is a young head of state, leading a just-formed party to probable victory.
May is a 60-year-old right-wing veteran who bungled a snap election and faces pressure to go from within her own party.
Setbacks for Eurosceptics
While the European Union looked fragile at the time of the Brexit vote, the eurosceptics have suffered setbacks since in elections in Austria, the Netherlands and France.
Macron is fervently pro-EU and wants to prove the bloc can protect its citizens in an age of globalisation.
And the French hope that Brexit will boost their finance sector at the expense of the City of London.
The two leaders are set to hold a press conference, have a brief dinner and attend a friendly football match between England and France, where there will be a minute's silence to honour the victims of the London and Manchester terror attacks.