After the draft deal was published two weeks ago, an irate editorial in the French newspaper Le Monde fumed that the concessions made to Britain were "exorbitant".
And while some in Mr Cameron's own Conservative Party dismiss his renegotiation as a watery fudge, politicians in Paris have a very different view.
Of particular concern here is the question of future financial regulation. UK ministers, too, think this is the most important part of the whole renegotiation.
The issue is this: The majority of EU countries that have the euro are integrating further and building a banking union with common rules and regulations. That process will deepen in the coming years.
Mr Cameron wants legal guarantees that the eurozone will not rig the rules in a way that could harm the interests of countries that do not have the euro. But France frets that the UK is seeking special treatment for the City of London, that could harm the single market in financial services.
France is also concerned a new mechanism that would allow non-euro countries to escalate their concerns could clog up decision-making.
The UK insists it is not asking for any veto or competitive advantage, but this is likely to be the focus of the hastily arranged talks here this evening.
President Hollande also faces an election next year - and while he wants the UK to stay in the EU, he will not do a deal that gives his opponents a chance to claim he sold out to Britain.
EU renegotiation: Did Cameron get what he wanted?
Referendum timeline: What will happen when?
The view from Europe: What's in it for the others?
More: BBC News EU referendum special

The WDBS was launched this week to give more people with disabilities the opportunity to play cue sports.
The first event will take place on 28 and 29 November at the South West Snooker Academy in Gloucester.
Five different disability classification groups will participate at the tournament.
The WDBS has been set up under the auspices of the World Professional Billiards and Snooker Association, with help from the English Federation of Disability Sport.
"We are delighted to announce the tournament and are sure it will be a great success," said WDBS chairman Nigel Mawer.
"We encourage anyone eligible to take part regardless of their snooker standard. It's a fantastic opportunity to meet others, get free coaching, and compete in a competitive environment."

About 20 people are currently living in the former car showroom on Iffley Road after moving in on New Year's Eve.
Leaseholder Midcounties Co-operative has said the squatters can stay until April, despite a judge granting it permission to evict them earlier.
But owner Oxford University's Wadham College said it requires the building back by 27 February.
This is so preparations for demolition can begin, the college said, as it intends to use the site for student housing.
Neo, a spokesman for the Iffley Open House campaign group, said it was "unacceptable" for the college to try to get the squatters out by February.
He added: "The weather will still be cold, I don't want people out on the streets."
The campaigners have asked that the building, which has been empty for two years, be officially designated as homeless housing.
Kevin Brown, group general manager at the Midcounties Co-operative, said in April the company has a legal obligation to hand the site back to Wadham College.
He added: "To ensure we're able to meet that requirement, we have been granted a repossession order but our preference is not to have to use it."
A Wadham College spokesperson said: "Whilst we have deep sympathy with the plight of homeless people, any solution must not delay the redevelopment of the building as homes for students.
"We will continue our discussions with all parties in the hope of resolving this amicably and are seeking help from local homeless support groups and charities to help find longer-term accommodation for these homeless people."

5 November 2015 Last updated at 17:26 GMT
It is a staggering number, and represents double the figure reported in April.
What is more it appears to dwarf the billion views YouTube clocks up daily, although it is not a true like-for-like comparison.
Facebook's aggressive push into video will surely delight advertisers who can promote their products alongside popular clips.
But YouTube star Tom Ridgewell - who has nearly four million followers on YouTube - told the BBC he was not convinced that Facebook was a big threat to Google's service.
Prime Minister David Cameron is to meet French President Francois Hollande in Paris shortly - the latest leg in his drive to negotiate new EU membership terms for the UK.
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The first tournament staged by the new World Disability Billiards and Snooker (WDBS) body will take place in Gloucester in November.
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Squatters who turned an Oxford building into a homeless shelter have been given temporary permission to stay.
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More than eight billion videos are now viewed on Facebook every day, according to the social network.