David Cameron will travel to Paris this evening for talks with President Francois Hollande ahead of this week's crunch EU summit, Downing Street has announced.
The Prime Minister must win over Mr Hollande on proposals for protections for non-eurozone states, which have caused consternation in the French capital.
Mr Cameron is insisting on legally-binding assurances that countries which do not use the single currency will not face discrimination as the eurozone integrates further.
But France has made clear that it will resist anything which looks like special treatment for the City of London.
The meeting comes at the start of a key week for Mr Cameron's EU renegotiation, with leaders set to try to agree a deal at a European Council summit on Thursday and Friday.
David Cameron has warned that Britain has "100 days to secure our future", as a poll suggests the final result hangs in the balance.
The EU referendum is a choice between "the devil and the deep blue sea", one of the UK's most senior business leaders is to say today.
Britain's car industry is an economic success story, and with uncertainty over the impact of Brexit, it wants to stay put.